Abstract

Influences of annealing on optical properties of spray pyrolysis deposited Cu-doped CdS (CdS:Cu) thin-films are investigated and designed Ag/CdS:Cu/FTO/glass based Schottky diode performances are discussed in detail. The sizes of the thin film are estimated through field-emission scanning electron microscopy (FESEM) images, exhibited that the films are composed of different-size, which increases with increasing the annealing temperature. The band-gap decreases from 2.79 eV to 2.75 eV with incresing annealing temperatures. According to I-V measurement, the ideality factor (& eta;), potential height (& phi;h) and series resistance (Rh) of Ag/CdS:Cu/FTO/glass Schottky diodes are estimated by various methods like thermionic-emission, Cheung and Norde, these all methods are consistent well. The ideality-factor and series-resistance decrease with increasing temperature and size. When the CdS:Cu thin-films are annealed at 400 degrees C, the Ag/CdS:Cu Schottky diodes have good rectifying behaviors with an ideality-factor of 4.67-5.03, a Schottky-potential height of 0.98 eV-0.87 eV and relatively low series-resistance of 2.35k & omega;-3.12k & omega;. The present study will give a better understanding and insight into the Ag/ CdS:Cu/FTO/glass Schottky junction.