Displaying publications 1 - 20 of 88 in total

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  1. Fulltext Significant Broadband Photocurrent Enhancement by Au-CZTS Core-Shell Nanostructured Photocathodes
    Zhang X, Wu X, Centeno A, Ryan MP, Alford NM, Riley DJ, et al.
    Sci Rep, 2016;6:23364.
    PMID: 26997140 DOI: 10.1038/srep23364
    Copper zinc tin sulfide (CZTS) is a promising material for harvesting solar energy due to its abundance and non-toxicity. However, its poor performance hinders their wide application. In this paper gold (Au) nanoparticles are successfully incorporated into CZTS to form Au@CZTS core-shell nanostructures. The photocathode of Au@CZTS nanostructures exhibits enhanced optical absorption characteristics and improved incident photon-to-current efficiency (IPCE) performance. It is demonstrated that using this photocathode there is a significant increase of the power conversion efficiency (PCE) of a photoelectrochemical solar cell of 100% compared to using a CZTS without Au core. More importantly, the PCE of Au@CZTS photocathode improved by 15.8% compared to standard platinum (Pt) counter electrode. The increased efficiency is attributed to plasmon resonance energy transfer (PRET) between the Au nanoparticle core and the CZTS shell at wavelengths shorter than the localized surface plasmon resonance (LSPR) peak of the Au and the semiconductor bandgap.
    Matched MeSH terms: Semiconductors
  2. Photoluminescence Investigation of Carrier Localization in Colloidal PbS and PbS/MnS Quantum Dots
    Zaini MS, Liew JYC, Alang Ahmad SA, Mohmad AR, Ahmad Kamarudin M
    ACS Omega, 2020 Dec 08;5(48):30956-30962.
    PMID: 33324803 DOI: 10.1021/acsomega.0c03768
    The existence of surface organic capping ligands on quantum dots (QDs) has limited the potential in QDs emission properties and energy band gap structure alteration as well as the carrier localization. This drawback can be addressed via depositing a thin layer of a semiconductor material on the surface of QDs. Herein, we report on the comparative study for photoluminescent (PL) properties of PbS and PbS/MnS QDs. The carrier localization effect due to the alteration of energy band gap structure and carrier recombination mechanism in the QDs were investigated via PL measurements in a temperature range of 10-300 K with the variation of the excitation power from 10 to 200 mW. For PbS QDs, the gradient of integrated PL intensity (IPL) as a function of excitation power density graph was less than unity. When the MnS shell layer was deposited onto the PbS core, the PL emission exhibited a blue shift, showing dominant carrier recombination. It was also found that the full width half-maximum showed a gradual broadening with the increasing temperature, affirming the electron-phonon interaction.
    Matched MeSH terms: Semiconductors
  3. Repeat analysis of intraoral digital imaging performed by undergraduate students using a complementary metal oxide semiconductor sensor: An institutional case study
    Yusof MYPM, Rahman NLA, Asri AAA, Othman NI, Wan Mokhtar I
    Imaging Sci Dent, 2017 Dec;47(4):233-239.
    PMID: 29279822 DOI: 10.5624/isd.2017.47.4.233
    Purpose: This study was performed to quantify the repeat rate of imaging acquisitions based on different clinical examinations, and to assess the prevalence of error types in intraoral bitewing and periapical imaging using a digital complementary metal-oxide-semiconductor (CMOS) intraoral sensor.

    Materials and Methods: A total of 8,030 intraoral images were retrospectively collected from 3 groups of undergraduate clinical dental students. The type of examination, stage of the procedure, and reasons for repetition were analysed and recorded. The repeat rate was calculated as the total number of repeated images divided by the total number of examinations. The weighted Cohen's kappa for inter- and intra-observer agreement was used after calibration and prior to image analysis.

    Results: The overall repeat rate on intraoral periapical images was 34.4%. A total of 1,978 repeated periapical images were from endodontic assessment, which included working length estimation (WLE), trial gutta-percha (tGP), obturation, and removal of gutta-percha (rGP). In the endodontic imaging, the highest repeat rate was from WLE (51.9%) followed by tGP (48.5%), obturation (42.2%), and rGP (35.6%). In bitewing images, the repeat rate was 15.1% and poor angulation was identified as the most common cause of error. A substantial level of intra- and interobserver agreement was achieved.

    Conclusion: The repeat rates in this study were relatively high, especially for certain clinical procedures, warranting training in optimization techniques and radiation protection. Repeat analysis should be performed from time to time to enhance quality assurance and hence deliver high-quality health services to patients.

    Matched MeSH terms: Semiconductors
  4. Fulltext Synthesis of a nano-silver metal ink for use in thick conductive film fabrication applied on a semiconductor package
    Yung LC, Fei CC, Mandeep J, Binti Abdullah H, Wee LK
    PLoS One, 2014;9(5):e97484.
    PMID: 24830317 DOI: 10.1371/journal.pone.0097484
    The success of printing technology in the electronics industry primarily depends on the availability of metal printing ink. Various types of commercially available metal ink are widely used in different industries such as the solar cell, radio frequency identification (RFID) and light emitting diode (LED) industries, with limited usage in semiconductor packaging. The use of printed ink in semiconductor IC packaging is limited by several factors such as poor electrical performance and mechanical strength. Poor adhesion of the printed metal track to the epoxy molding compound is another critical factor that has caused a decline in interest in the application of printing technology to the semiconductor industry. In this study, two different groups of adhesion promoters, based on metal and polymer groups, were used to promote adhesion between the printed ink and the epoxy molding substrate. The experimental data show that silver ink with a metal oxide adhesion promoter adheres better than silver ink with a polymer adhesion promoter. This result can be explained by the hydroxyl bonding between the metal oxide promoter and the silane grouping agent on the epoxy substrate, which contributes a greater adhesion strength compared to the polymer adhesion promoter. Hypotheses of the physical and chemical functions of both adhesion promoters are described in detail.
    Matched MeSH terms: Semiconductors*
  5. In vitro anti-breast cancer studies of LED red light therapy through autophagy
    Yang KL, Khoo BY, Ong MT, Yoong ICK, Sreeramanan S
    Breast Cancer, 2021 Jan;28(1):60-66.
    PMID: 32654094 DOI: 10.1007/s12282-020-01128-6
    LED red light has been reported to have many health benefits. The present study was conducted to characterise anti-proliferation properties of four LED red light wavelengths (615, 630, 660 and 730 nm) against non-triple negative (MCF-7) and triple negative (MDA-MB-231) breast cancer-origin cell lines. It has been shown by MTT assay that at 24 h post-exposure time point, only LED red light with wavelength 660 nm possessed anti-proliferative effects against both cell lines with 40% reduction of cell viability. The morphology of LED 660 nm irradiated cells was found flatten with enlarged cell size, typical characteristic of cell senescent. Indications of autophagy activities following the irradiation have been provided by acridine orange staining, showing high presence of acidic vesicle organelles (AVOs). In addition, high LC3-II/LC3-I to LC3 ratio has been observed qualitatively in Western blot analysis indicating an increase number of autophagosomes formation in LED 660 nm irradiated cells compared to control cells. Electron dense bodies observed in these cells under TEM micrographs provided additional support to the above observations, leading to the conclusion that LED 660 nm irradiation promoted anti-proliferative activities through autophagy in breast cancer-origin cells. These findings have suggested that LED 660 nm might be developed and be employed as an alternative cancer treatment method in future.
    Matched MeSH terms: Semiconductors
  6. Sulfur-doped graphitic carbon nitride incorporated bismuth oxychloride/Cobalt based type-II heterojunction as a highly stable material for photoelectrochemical water splitting
    Vinoth S, Ong WJ, Pandikumar A
    J Colloid Interface Sci, 2021 Jun;591:85-95.
    PMID: 33592528 DOI: 10.1016/j.jcis.2021.01.104
    Cobalt incorporated sulfur-doped graphitic carbon nitride with bismuth oxychloride (Co/S-gC3N4/BiOCl) heterojunction is prepared by an ultrasonically assisted hydrothermal treatment. The heterojunction materials have employed in photoelectrochemical (PEC) water splitting. The PEC activity and stability of the materials are promoted by constructing an interface between the visible light active semiconductor photocatalyst and cocatalysts. The photocurrent density of Co-9% S-gC3N4/BiOCl has attained 393.0 μA cm-2 at 1.23 V vs. RHE, which is 7-fold larger than BiOCl and ~3-fold higher than 9% S-gC3N4/BiOCl. The enhanced PEC activity can be attributed to the improved electron-hole charge separation and the boosted charge transfer is confirmed by photoluminescence (PL) and electrochemical impedance spectroscopy (EIS) analysis. The fabricated Co/S-gC3N4/BiOCl nanohybrid material has exhibited high stability of up to 10,800 s (3 h) at 1.23 V vs. RHE during PEC water splitting reaction and the obtained photo-conversion efficiency is 3.7-fold greater than S-gC3N4/BiOCl and 17-fold higher than BiOCl. The FESEM and HRTEM images have revealed the formation of heterojunction interface between S-gC3N4 and BiOCl and the elemental mapping has confirmed the presence of cobalt over S-gC3N4/BiOCl. The heterojunction interface has facilitated the photo-excited charge separation and transport across the electrode/electrolyte interface and also the flat-band potential, which is confirmed by Mott-Schottky analysis.
    Matched MeSH terms: Semiconductors
  7. Perovskite Flash Memory with a Single-Layer Nanofloating Gate
    Vasilopoulou M, Kim BS, Kim HP, da Silva WJ, Schneider FK, Mat Teridi MA, et al.
    Nano Lett., 2020 Jul 08;20(7):5081-5089.
    PMID: 32492348 DOI: 10.1021/acs.nanolett.0c01270
    Here we use triple-cation metal-organic halide perovskite single crystals for the transistor channel of a flash memory device. Moreover, we design and demonstrate a 10 nm thick single-layer nanofloating gate. It consists of a ternary blend of two organic semiconductors, a p-type polyfluorene and an n-type fullerene that form a donor:acceptor interpenetrating network that serves as the charge storage unit, and of an insulating polystyrene that acts as the tunneling dielectric. Under such a framework, we realize the first non-volatile flash memory transistor based on a perovskite channel. This simplified, solution-processed perovskite flash memory displays unique performance metrics such as a large memory window of 30 V, an on/off ratio of 9 × 107, short write/erase times of 50 ms, and a satisfactory retention time exceeding 106 s. The realization of the first flash memory transistor using a single-crystal perovskite channel could be a valuable direction for perovskite electronics research.
    Matched MeSH terms: Semiconductors
  8. Fulltext Light-Addressable Potentiometric Sensors Using ZnO Nanorods as the Sensor Substrate for Bioanalytical Applications
    Tu Y, Ahmad N, Briscoe J, Zhang DW, Krause S
    Anal Chem, 2018 07 17;90(14):8708-8715.
    PMID: 29932632 DOI: 10.1021/acs.analchem.8b02244
    Light-addressable potentiometric sensors (LAPS) are of great interest in bioimaging applications such as the monitoring of concentrations in microfluidic channels or the investigation of metabolic and signaling events in living cells. By measuring the photocurrents at electrolyte-insulator-semiconductor (EIS) and electrolyte-semiconductor structures, LAPS can produce spatiotemporal images of chemical or biological analytes, electrical potentials and impedance. However, its commercial applications are often restricted by their limited AC photocurrents and resolution of LAPS images. Herein, for the first time, the use of 1D semiconducting oxides in the form of ZnO nanorods for LAPS imaging is explored to solve this issue. A significantly increased AC photocurrent with enhanced image resolution has been achieved based on ZnO nanorods, with a photocurrent of 45.7 ± 0.1 nA at a light intensity of 0.05 mW, a lateral resolution as low as 3.0 μm as demonstrated by images of a PMMA dot on ZnO nanorods and a pH sensitivity of 53 mV/pH. The suitability of the device for bioanalysis and bioimaging was demonstrated by monitoring the degradation of a thin poly(ester amide) film with the enzyme α-chymotrypsin using LAPS. This simple and robust route to fabricate LAPS substrates with excellent performance would provide tremendous opportunities for bioimaging.
    Matched MeSH terms: Semiconductors
  9. Fulltext Role of morphological structure, doping, and coating of different materials in the sensing characteristics of humidity sensors
    Tripathy A, Pramanik S, Cho J, Santhosh J, Osman NA
    Sensors (Basel), 2014;14(9):16343-422.
    PMID: 25256110 DOI: 10.3390/s140916343
    The humidity sensing characteristics of different sensing materials are important properties in order to monitor different products or events in a wide range of industrial sectors, research and development laboratories as well as daily life. The primary aim of this study is to compare the sensing characteristics, including impedance or resistance, capacitance, hysteresis, recovery and response times, and stability with respect to relative humidity, frequency, and temperature, of different materials. Various materials, including ceramics, semiconductors, and polymers, used for sensing relative humidity have been reviewed. Correlations of the different electrical characteristics of different doped sensor materials as the most unique feature of a material have been noted. The electrical properties of different sensor materials are found to change significantly with the morphological changes, doping concentration of different materials and film thickness of the substrate. Various applications and scopes are pointed out in the review article. We extensively reviewed almost all main kinds of relative humidity sensors and how their electrical characteristics vary with different doping concentrations, film thickness and basic sensing materials. Based on statistical tests, the zinc oxide-based sensing material is best for humidity sensor design since it shows extremely low hysteresis loss, minimum response and recovery times and excellent stability.
    Matched MeSH terms: Semiconductors*
  10. Fulltext Incoming Work-In-Progress Prediction in Semiconductor Fabrication Foundry Using Long Short-Term Memory
    Tin TC, Chiew KL, Phang SC, Sze SN, Tan PS
    Comput Intell Neurosci, 2019;2019:8729367.
    PMID: 30719036 DOI: 10.1155/2019/8729367
    Preventive maintenance activities require a tool to be offline for long hour in order to perform the prescribed maintenance activities. Although preventive maintenance is crucial to ensure operational reliability and efficiency of the tool, long hour of preventive maintenance activities increases the cycle time of the semiconductor fabrication foundry (Fab). Therefore, this activity is usually performed when the incoming Work-in-Progress to the equipment is forecasted to be low. The current statistical forecasting approach has low accuracy because it lacks the ability to capture the time-dependent behavior of the Work-in-Progress. In this paper, we present a forecasting model that utilizes machine learning method to forecast the incoming Work-In-Progress. Specifically, our proposed model uses LSTM to forecast multistep ahead incoming Work-in-Progress prediction to an equipment group. The proposed model's prediction results were compared with the results of the current statistical forecasting method of the Fab. The experimental results demonstrated that the proposed model performed better than the statistical forecasting method in both hit rate and Pearson's correlation coefficient, r.
    Matched MeSH terms: Semiconductors
  11. Device and circuit-level performance of carbon nanotube field-effect transistor with benchmarking against a nano-MOSFET
    Tan ML, Lentaris G, Amaratunga Aj G
    Nanoscale Res Lett, 2012;7(1):467.
    PMID: 22901374
    The performance of a semiconducting carbon nanotube (CNT) is assessed and tabulated for parameters against those of a metal-oxide-semiconductor field-effect transistor (MOSFET). Both CNT and MOSFET models considered agree well with the trends in the available experimental data. The results obtained show that nanotubes can significantly reduce the drain-induced barrier lowering effect and subthreshold swing in silicon channel replacement while sustaining smaller channel area at higher current density. Performance metrics of both devices such as current drive strength, current on-off ratio (Ion/Ioff), energy-delay product, and power-delay product for logic gates, namely NAND and NOR, are presented. Design rules used for carbon nanotube field-effect transistors (CNTFETs) are compatible with the 45-nm MOSFET technology. The parasitics associated with interconnects are also incorporated in the model. Interconnects can affect the propagation delay in a CNTFET. Smaller length interconnects result in higher cutoff frequency.
    Matched MeSH terms: Semiconductors
  12. Fulltext Ultra-low-voltage CMOS-based current bleeding mixer with high LO-RF isolation
    Tan GH, Sidek RM, Ramiah H, Chong WK, Lioe de X
    ScientificWorldJournal, 2014;2014:163414.
    PMID: 25197694 DOI: 10.1155/2014/163414
    This journal presents an ultra-low-voltage current bleeding mixer with high LO-RF port-to-port isolation, implemented on 0.13 μm standard CMOS technology for ZigBee application. The architecture compliments a modified current bleeding topology, consisting of NMOS-based current bleeding transistor, PMOS-based switching stage, and integrated inductors achieving low-voltage operation and high LO-RF isolation. The mixer exhibits a conversion gain of 7.5 dB at the radio frequency (RF) of 2.4 GHz, an input third-order intercept point (IIP3) of 1 dBm, and a LO-RF isolation measured to 60 dB. The DC power consumption is 572 µW at supply voltage of 0.45 V, while consuming a chip area of 0.97 × 0.88 mm(2).
    Matched MeSH terms: Semiconductors*
  13. Fulltext Influence of Irradiation Time on the Structural and Optical Characteristics of CuSe Nanoparticles Synthesized via Microwave-Assisted Technique
    Shitu IG, Liew JYC, Talib ZA, Baqiah H, Awang Kechik MM, Ahmad Kamarudin M, et al.
    ACS Omega, 2021 Apr 27;6(16):10698-10708.
    PMID: 34056223 DOI: 10.1021/acsomega.1c00148
    A rapid, sustainable, and ecologically sound approach is urgently needed for the production of semiconductor nanomaterials. CuSe nanoparticles (NPs) were synthesized via a microwave-assisted technique using CuCl2·2H2O and Na2SeO3 as the starting materials. The role of the irradiation time was considered as the primary concern to regulate the size and possibly the shape of the synthesized nanoparticles. A range of characterization techniques was used to elucidate the structural and optical properties of the fabricated nanoparticles, which included X-ray diffraction, energy-dispersive X-ray spectroscopy (EDX), atomic force microscopy, field emission scanning electron microscopy, Raman spectroscopy (Raman), UV-Visible diffuse reflectance spectroscopy (DRS), and photoluminescence spectroscopy (PL). The mean crystallite size of the CuSe hexagonal (Klockmannite) crystal structure increased from 21.35 to 99.85 nm with the increase in irradiation time. At the same time, the microstrain and dislocation density decreased from 7.90 × 10-4 to 1.560 × 10-4 and 4.68 × 10-2 to 1.00 × 10-2 nm-2, respectively. Three Raman vibrational bands attributed to CuSe NPs have been identified in the Raman spectrum. Irradiation time was also seen to play a critical role in the NP optical band gap during the synthesis. The decrease in the optical band gap from 1.85 to 1.60 eV is attributed to the increase in the crystallite size when the irradiation time was increased. At 400 nm excitation wavelength, a strong orange emission centered at 610 nm was observed from the PL measurement. The PL intensity is found to increase with an increase in irradiation time, which is attributed to the improvement in crystallinity at higher irradiation time. Therefore, the results obtained in this study could be of great benefit in the field of photonics, solar cells, and optoelectronic applications.
    Matched MeSH terms: Semiconductors
  14. Solution-Processable Vertical Organic Light-Emitting Transistors (VOLETs) with Directly Deposited Silver Nanowires Intermediate Source Electrode
    Sarjidan MAM, Shuhaimi A, Majid WHA
    J Nanosci Nanotechnol, 2019 Nov 01;19(11):6995-7003.
    PMID: 31039852 DOI: 10.1166/jnn.2019.16724
    A simple spin-coating process for fabricating vertical organic light-emitting transistors (VOLETs) is realized by utilizing silver nanowire (AgNW) as a source electrode. The optical, electrical and morphological properties of the AgNW formation was initially optimized, prior VOFET fabrication. A high molecular weight of poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] MEH-PPV was used as an organic semiconductor layer in the VOFET in forming a multilayer structure by solution process. It was found that current density and luminance intensity of the VOLET can be modulated by a small magnitude of gate voltage. The modulation process was induced by changing an injection barrier via gate voltage bias. A space-charge-limited current (SCLC) approach in determining transistor mobility has been introduced. This preliminary and fundamental work is beneficial towards all-solution processing display devices.
    Matched MeSH terms: Semiconductors
  15. Stretchable AgX (X = Se, Te) for Efficient Thermoelectrics and Photovoltaics
    Robin Chang YH, Jiang J, Khong HY, Saad I, Chai SS, Mahat MM, et al.
    ACS Appl Mater Interfaces, 2021 Jun 02;13(21):25121-25136.
    PMID: 34008948 DOI: 10.1021/acsami.1c04759
    Transition metal chalcogenides (TMCs) have gained worldwide interest owing to their outstanding renewable energy conversion capability. However, the poor mechanical flexibility of most existing TMCs limits their practical commercial applications. Herein, triggered by the recent and imperative synthesis of highly ductile α-Ag2S, an effective approach based on evolutionary algorithm and ab initio total-energy calculations for determining stable, ductile phases of bulk and two-dimensional Ag
    x
    Se1-x and Ag
    x
    Te1-x compounds was implemented. The calculations correctly reproduced the global minimum bulk stoichiometric P212121-Ag8Se4 and P21/c-Ag8Te4 structures. Recently reported metastable AgTe3 was also revealed but it lacks dynamical stability. Further single-layered screening unveiled two new monolayer P4/nmm-Ag4Se2 and C2-Ag8Te4 phases. Orthorhombic Ag8Se4 crystalline has a narrow, direct band gap of 0.26 eV that increases to 2.68 eV when transforms to tetragonal Ag4Se2 monolayer. Interestingly, metallic P21/c-Ag8Te4 changes to semiconductor when thinned down to monolayer, exhibiting a band gap of 1.60 eV. Present findings confirm their strong stability from mechanical and thermodynamic aspects, with reasonable Vickers hardness, bone-like Young's modulus (E) and high machinability observed in bulk phases. Detailed analysis of the dielectric functions ε(ω), absorption coefficient α(ω), power conversion efficiency (PCE) and refractive index n(ω) of monolayers are reported for the first time. Fine theoretical PCE (SLME method ∼11-28%), relatively high n(0) (1.59-1.93), and sizable α(ω) (104-105 cm-1) that spans the infrared to visible regions indicate their prospects in optoelectronics and photoluminescence applications. Effective strategies to improve the temperature dependent power factor (PF) and figure of merit (ZT) are illustrated, including optimizing the carrier concentration. With decreasing thickness, ZT of p-doped Ag-Se was found to rise from approximately 0.15-0.90 at 300 K, leading to a record high theoretical conversion efficiency of ∼12.0%. The results presented foreshadow their potential application in a hybrid device that combines the photovoltaic and thermoelectric technologies.
    Matched MeSH terms: Semiconductors
  16. Fulltext Photopyroelectric spectroscopic studies of ZnO-MnO(2)-Co(3)O(4)-V(2)O(5) ceramics
    Rizwan Z, Zakaria A, Ghazali MS
    Int J Mol Sci, 2011;12(3):1625-32.
    PMID: 21673911 DOI: 10.3390/ijms12031625
    Photopyroelectric (PPE) spectroscopy is a nondestructive tool that is used to study the optical properties of the ceramics (ZnO + 0.4MnO(2) + 0.4Co(3)O(4) + xV(2)O(5)), x = 0-1 mol%. Wavelength of incident light, modulated at 10 Hz, was in the range of 300-800 nm. PPE spectrum with reference to the doping level and sintering temperature is discussed. Optical energy band-gap (E(g)) was 2.11 eV for 0.3 mol% V(2)O(5) at a sintering temperature of 1025 °C as determined from the plot (ρhυ)(2)versushυ. With a further increase in V(2)O(5), the value of E(g) was found to be 2.59 eV. Steepness factor 'σ(A)' and 'σ(B)', which characterize the slope of exponential optical absorption, is discussed with reference to the variation of E(g). XRD, SEM and EDAX are also used for characterization of the ceramic. For this ceramic, the maximum relative density and grain size was observed to be 91.8% and 9.5 μm, respectively.
    Matched MeSH terms: Semiconductors
  17. Electrical behaviour of MEH-PPV based diode and transistor
    Reshak AH, Shahimin MM, Juhari N, Suppiah S
    Prog Biophys Mol Biol, 2013 Nov;113(2):289-94.
    PMID: 24080185 DOI: 10.1016/j.pbiomolbio.2013.09.002
    The potential of organic semiconductor based devices for light generation is demonstrated by the commercialisation of display technologies using organic light emitting diode (OLED). In OLED, organic materials plays an important role of emitting light once the current is passed through. However OLED have drawbacks whereby it suffers from photon loss and exciton quenching. Organic light emitting transistor (OLET) emerged as a new technology to compensate the efficiency and brightness loss encountered in OLED. The structure has combinational capability to switch the electronic signal such as the field effect transistor (FET) as well as to generate light. Different colours of light could be generated by using different types of organic material. The light emission could also be tuned and scanned in OLET. The studies carried out in this paper focuses on investigation of fabricated MEH-PPV based OLED and also OLET via current voltage characteristics. These studies will continue with a view to develop an optimised MEH-PPV based OLET.
    Matched MeSH terms: Semiconductors*
  18. Fulltext Study of growth in Bi2Sr2CaCu2Oy single crystals
    Razak Mohd Ali Lee, Khairul Anwar Mohamad, Katsuyoshi, Hamasaki
    Journal of Nuclear and Related Technologies, 2007;2007(1):195-198.
    MyJurnal
    We put attention on Intrinsic Josephson Junction (IJJ) to study the fundamental physic for device applications. Convenient self-flux method was used to grow BSCCO single crystals. We investigated the lid effect to examine the single crystal growth of high TC (Critical Temperature). We found that for the crystal growth with no lid, two stage transitions of TC ≅ 61 K and 77 K were observed. While for the crystal growth with lid, the BSCCO has TC ≅ 80K, ΔTC = 10K and approximately average size5x2mm 2 . When we increased weight of lid, the single crystal have increased to TC =80K, ΔTC = 4K and the typical size was ≅7x3mm 2 . TC and the crystal growth show a tendency to increase by the effect of the lid. From observed quasi-particle characteristics, c-axis direction changed from semiconductor to intrinsic Josephson characteristic with decreasing temperature.
    Matched MeSH terms: Semiconductors
  19. Fulltext Analytical modeling of trilayer graphene nanoribbon Schottky-barrier FET for high-speed switching applications
    Rahmani M, Ahmadi MT, Abadi HK, Saeidmanesh M, Akbari E, Ismail R
    Nanoscale Res Lett, 2013;8(1):55.
    PMID: 23363692 DOI: 10.1186/1556-276X-8-55
    Recent development of trilayer graphene nanoribbon Schottky-barrier field-effect transistors (FETs) will be governed by transistor electrostatics and quantum effects that impose scaling limits like those of Si metal-oxide-semiconductor field-effect transistors. The current-voltage characteristic of a Schottky-barrier FET has been studied as a function of physical parameters such as effective mass, graphene nanoribbon length, gate insulator thickness, and electrical parameters such as Schottky barrier height and applied bias voltage. In this paper, the scaling behaviors of a Schottky-barrier FET using trilayer graphene nanoribbon are studied and analytically modeled. A novel analytical method is also presented for describing a switch in a Schottky-contact double-gate trilayer graphene nanoribbon FET. In the proposed model, different stacking arrangements of trilayer graphene nanoribbon are assumed as metal and semiconductor contacts to form a Schottky transistor. Based on this assumption, an analytical model and numerical solution of the junction current-voltage are presented in which the applied bias voltage and channel length dependence characteristics are highlighted. The model is then compared with other types of transistors. The developed model can assist in comprehending experiments involving graphene nanoribbon Schottky-barrier FETs. It is demonstrated that the proposed structure exhibits negligible short-channel effects, an improved on-current, realistic threshold voltage, and opposite subthreshold slope and meets the International Technology Roadmap for Semiconductors near-term guidelines. Finally, the results showed that there is a fast transient between on-off states. In other words, the suggested model can be used as a high-speed switch where the value of subthreshold slope is small and thus leads to less power consumption.
    Matched MeSH terms: Semiconductors
  20. Fulltext Design of high speed and low offset dynamic latch comparator in 0.18 µm CMOS process
    Rahman LF, Reaz MB, Yin CC, Ali MA, Marufuzzaman M
    PLoS One, 2014;9(10):e108634.
    PMID: 25299266 DOI: 10.1371/journal.pone.0108634
    The cross-coupled circuit mechanism based dynamic latch comparator is presented in this research. The comparator is designed using differential input stages with regenerative S-R latch to achieve lower offset, lower power, higher speed and higher resolution. In order to decrease circuit complexity, a comparator should maintain power, speed, resolution and offset-voltage properly. Simulations show that this novel dynamic latch comparator designed in 0.18 µm CMOS technology achieves 3.44 mV resolution with 8 bit precision at a frequency of 50 MHz while dissipating 158.5 µW from 1.8 V supply and 88.05 µA average current. Moreover, the proposed design propagates as fast as 4.2 nS with energy efficiency of 0.7 fJ/conversion-step. Additionally, the core circuit layout only occupies 0.008 mm2.
    Matched MeSH terms: Semiconductors
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