Resistance Study of Er-doped Zinc Oxide Diode by Spray Pyrolysis

Undoped and erbium-doped zinc oxide followed by indium-doped zinc oxide layers on p-type Si substrate were prepared by spray pyrolysis with zinc acetate, erbium acetate, and indium nitrate precursors. The surface morphology and crystalline quality were investigated. Using a front-and back-side metallization process, diodes were fabricated. The current-voltage characteristics of these diodes were analyzed. The structural resistance, which is an important issue in gas sensing application, shows an increase-decrease behavior with the increase of erbium contents in zinc oxide. With a reverse bias in excess of 6 V, two distinct green light emissions with 536 and 555 nm wavelength and one red light emission at around 664 nm of the 5% erbium-doped zinc oxide diode can be observed. The structural resistance character, as well as the ideality factor of these diodes were analyzed and discussed.