PROJECT TITLE :

Fabrication and Characterization of ZnO/p-Si and TiO2/p-Si Heterojunctions for Hydrogen Detection—Influence of Pd Functionalization

ABSTRACT:

Nanocrystallyne n-ZnO and p-TiO2 skinny films were deposited on crystalline Si substrate by the simple and low-cost sol-gel method. The surfaces of nanocrystalline ZnO and TiO2 were modified by PdCl2 solution to passivate the defect states and to boost the gas sensitivity. Both unmodified and Pd changed sensors with Pd-Ag/n-ZnO/p-Si/Al and Pd-Ag/p-TiO2/p-Si/Al device structures were exposed to totally different hydrogen concentrations (zero.01%, 0.05%, zero.1%, 0.5%, and 1%) at the optimum biasing voltage and temperature. The result of gas response was investigated using nitrogen along with synthetic air as the carrier gas. Each the sensor configurations showed the improved gas response after surface treatment with Pd ions. Surface modified p-TiO2 sensors recorded higher gas response (seventy eightpercent), response time (three s), and recovery time (seventy four s) compared with ZnO sensors under the similar conditions.