| Zinc telluride (ZnTe) is an attractive II-VI compound semiconductor with a direct bandgap of 2.26 eV that is used in many applications in optoelectronic devices. Compared to the two dimensional (2D) thin-film semiconductors, one-dimensional (1D) nanowires can have different electronic properties for potential novel applications. In this work, we present the study of ZnTe nanowires (NWs) that are synthesized through a simple vapor-liquid-solid (VLS) method. By controlling the presence or the absence of Au catalysts and controlling the growth parameters such as growth temperature, various growth morphologies of ZnTe, such as thin films and nanowires can be obtained. The characterization of the ZnTe nanostructures and films was performed using scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDX), high- resolution transmission electron microscope (HRTEM), X-ray diffraction (XRD), photoluminescence (PL), Raman spectroscopy and light scattering measurement. After confirming the crystal purity of ZnTe, two-terminal diodes and three-terminal transistors were fabricated with both nanowire and planar nano-sheet configurations, in order to correlate the nanostructure geometry to device performance including field effect mobility, Schottky barrier characteristics, and turn-on characteristics. Additionally, optoelectronic properties such as photoconductive gain and responsivity were compared against morphology. Finally, ZnTe was explored in conjunction with ZnO in order to form type-II band alignment in a core-shell nanostructure. Various characterization techniques including scanning electron microscopy, energy-dispersive X-ray spectroscopy , x-ray diffraction, Raman spectroscopy, UV-vis reflectance spectra and photoluminescence were used to investigate the modification of ZnO/ZnTe core/shell structure properties. In PL spectra, the eliminated PL intensity of ZnO wires is primarily attributed to the efficient charge transfer process occurring between ZnO and ZnTe, due to the band alignment in the core/shell structure. Moreover, the result of UV-vis reflectance spectra corresponds to the band gap energy of ZnO and ZnTe, respectively, which confirm that the sample consists of ZnO/ZnTe core/shell structure of good quality. |
