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Fulltext Synthesis of gallium nitride nanostructures by nitridation of electrochemically deposited gallium oxide on silicon substrate

Ghazali NM, Yasui K, Hashim AM

Nanoscale Res Lett, 2014;9(1):685.
PMID: 25593562 DOI: 10.1186/1556-276X-9-685

Gallium nitride (GaN) nanostructures were successfully synthesized by the nitridation of the electrochemically deposited gallium oxide (Ga2O3) through the utilization of a so-called ammoniating process. Ga2O3 nanostructures were firstly deposited on Si substrate by a simple two-terminal electrochemical technique at a constant current density of 0.15 A/cm(2) using a mixture of Ga2O3, HCl, NH4OH and H2O for 2 h. Then, the deposited Ga2O3 sample was ammoniated in a horizontal quartz tube single zone furnace at various ammoniating times and temperatures. The complete nitridation of Ga2O3 nanostructures at temperatures of 850°C and below was not observed even the ammoniating time was kept up to 45 min. After the ammoniating process at temperature of 900°C for 15 min, several prominent diffraction peaks correspond to hexagonal GaN (h-GaN) planes were detected, while no diffraction peak of Ga2O3 structure was detected, suggesting a complete transformation of Ga2O3 to GaN. Thus, temperature seems to be a key parameter in a nitridation process where the deoxidization rate of Ga2O3 to generate gaseous Ga2O increase with temperature. The growth mechanism for the transformation of Ga2O3 to GaN was proposed and discussed. It was found that a complete transformation can not be realized without a complete deoxidization of Ga2O3. A significant change of morphological structures takes place after a complete transformation of Ga2O3 to GaN where the original nanorod structures of Ga2O3 diminish, and a new nanowire-like GaN structures appear. These results show that the presented method seems to be promising in producing high-quality h-GaN nanostructures on Si.
Fulltext Electrochemically deposited gallium oxide nanostructures on silicon substrates

Ghazali NM, Mahmood MR, Yasui K, Hashim AM

Nanoscale Res Lett, 2014;9(1):120.
PMID: 24629107 DOI: 10.1186/1556-276X-9-120

We report a synthesis of β-Ga2O3 nanostructures on Si substrate by electrochemical deposition using a mixture of Ga2O3, HCl, NH4OH, and H2O. The presence of Ga3+ ions contributed to the deposition of Ga2O3 nanostructures on the Si surface with the assistance of applied potentials. The morphologies of the grown structures strongly depended on the molarity of Ga2O3 and pH level of electrolyte. β-Ga2O3 nanodot-like structures were grown on Si substrate at a condition with low molarity of Ga2O3. However, Ga2O3 nanodot structures covered with nanorods on top of their surfaces were obtained at higher molarity, and the densities of nanorods seem to increase with the decrease of pH level. High concentration of Ga3+ and OH- ions may promote the reaction of each other to produce Ga2O3 nanorods in the electrolyte. Such similar nature of Ga2O3 nanorods was also obtained by using hydrothermal process. The grown structures seem to be interesting for application in electronic and optoelectronic devices as well as to be used as a seed structure for subsequent chemical synthesis of GaN by thermal transformation method.
Outcome of Different Treatment Modalities of Fracture Zygoma

Rahman RA, Ghazali NM, Rahman NA, Pohchi A, Razak NHA

J Craniofac Surg, 2020 Jun;31(4):1056-1062.
PMID: 32176023 DOI: 10.1097/SCS.0000000000006297

OBJECTIVES: This study aimed to determine the pattern of fractured zygoma, different treatment modalities, and complications of the treatment in our center. It also aimed to determine the association between the treatment modalities and complication of treatment, and association between number of fixation and complication.
METHODOLOGY: A retrospective review was conducted from January 2008 until December 2011. All patients diagnosed with zygomatic complex fractured that met the inclusion and exclusion criteria were included in the study. Zingg's Classification was used in the study.
RESULTS: The median age was 23.5. Type A was the most common fracture type made up 26.6%. About 90.8% of the injury was caused by road traffic accident. Forty-four patients were treated with open reduction and internal fixation and 4 patients were treated with close reduction only. Fifty patients were treated conservatively. Gillies approach in combination with fixation is the most common procedure accounted for 50%. Three-point fixation at infraorbital, maxillary buttress, frontozygomatic suture, and zygomatic arch was the most common site. However, there were no significant associations between the number of fixation and the occurrence of the complication (P = 0.307). About 29.2% in the treatment group and 66% in the conservative group had complications. About 35.7% of patients in treatment group had complications, while 66% had trismus in conservative group.
CONCLUSION: There was a significant association between types of treatment and the occurrence of complication (P = 0.001). However, there were no significant association between number of fixation and the occurrence of complications (P = 0.307).

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