Characterization and applications of wide bandgap semiconductor materials

Abstract

Wide bandgap materials are potential candidates to revolutionize high-power electronics and optoelectronic devices due to their wide bandgap energy greater than 2 eV. Thus, there is a great necessity to research on these materials and implement in advanced applications to gain the advantages of these materials. This research work involves projects which are revolving around two different wide bandgap materials: zinc oxide (ZnO) and gallium nitride (GaN). A multi-layered hybrid ZnO based UV sensor has been developed using sol-gel and hydrothermal growth methods. Most of the reported ZnO nanostructure based ultraviolet photodetectors have in-built high resistance due to their limitations in single layer topological designs with poor photocurrent and high dark currents, and eventually these devices yield lower Ion/Ioff ratio, responsivity and detectivity. In this work, a device with improved photocurrent to dark current contrast ratio, photoresponsivity and detectivity has been developed. The second project comprises of GaN wafers which were doped in a high-quality manner by a neutron transmutation doping method. This work has resulted in consistently doped Ge atoms in the range of 1018/cm3. Defect studies have been a crucial part of standardizing the material processing, as the defect can alter electrical and optical properties of doped semiconductor materials. Using the deep level transient spectroscopy (DLTS), the defect analysis was carried out to understand the trap formation and electronic properties of the traps from irradiation doped samples in correlation to theoretical studies.