Development and Characterization of Sol-gel Derived Al Doped ZnO/p-Si Photodiode

The effect of Al doping on the J-V characteristics sol-gel derived of ZnO/p-Si photodiodes was investigated. The resistivity of Si was 0.1Ω·cm. ZnO films annealed at 500°C were of the best quality. To investigate the spectral response of the photodiodes, the J-V characteristics were measured under different monochromatic lights at wavelength 420, 530, 570 and 630 nm. The diodes exhibit strong responsivity in the blue region at 420 nm. The responsivity is 0.22 A/W for Al doped (0.8 wt pct) photodiode, whereas for the undoped photodiode, it was much lower. An estimate of the responsivity as a function of wavelength has been made in terms of the width of depletion region of photodiodes.