Zinc selenide/graphene oxide (ZnSe/GO) composite is synthesized using hydrothermal method. Two different methods
such as direct and indirect route have been investigated to form the ZnSe/GO composite. In this research, the graphene
oxide used was in sheet and liquid form. The synthesized composite was then characterized using X-ray diffraction (XRD)
for phase identification, field emission scanning electron microscopy (FESEM) for morphology analysis and ultravioletvisible
spectroscopy (UV-Vis) for optical properties. ZnSe/GO composite showed absorption peak ranging from 460 to
480 nm with the optical band gap obtained through Tauc equation. The optical band gap of the ZnSe/GO composite has
been tuned down to a smaller value as compared to the bulk ZnSe compound. The optical band gap has been reduced
to around 2.53 eV when liquid graphene oxide was used while around 2.23 to 2.32 eV when graphene oxide sheet was
used. The purity of ZnSe/GO composite synthesis via indirect hydrothermal method is higher than those synthesized via
direct hydrothermal method. The type of graphene oxide will affect the morphology of the composite where the ZnSe
compound was either wrapped by tiny thorn-like substance or graphene oxide layer.
Zinc selenide (ZnSe) quantum dots (QDs) have been synthesized through a hydrothermal method using ZnCl2
and Na2
SeO3
powder as the precursor in the presence of oleylamine as capping agent. The hydrothermal route was conducted at a
moderate temperature (150°C) for 8 h. Optical properties of ZnSe QDs were studied through ultraviolet-visible spectroscopy
(UV-Vis) and photoluminescence (PL) while the structural properties of ZnSe QDs were characterized using transmission
electron microscope (TEM). The photoluminescence (PL) characterization on ZnSe QDs showed that the QDs emit light in
blue range region at around 440 nm with optical band gap energy at 3.68 eV. The TEM results showed that the average
particle size is around 8.9 nm. It is a good candidates for optoelectronic devices such as light emitting diodes (LED).