Characterization of films and interfaces in n-ZnO/p-Si photodiodes

• Published in: Thin solid films 2002-12, Vol.420, p.112-116
• Main Authors: Lee, J.Y., Choi, Y.S., Choi, W.H., Yeom, H.W., Yoon, Y.K., Kim, J.H., Im, S.
• Format: Article
• Language: English
• Subjects: Current–voltage; Interface junction; Leakage current; n-ZnO/p-Si photodiode; Photoelectric
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/S0040-6090(02)00742-3

We report on the fabrication of n-ZnO/p-Si heterojunction photodiodes. RF sputtering was performed to deposit ZnO films on p-Si substrates at various substrate temperatures of 300, 480 and 550 °C using Ar:O 2 ratios of 6:1. Typical rectifying behaviors were observed from most of the diodes as characterized by the current–voltage ( I– V) measurement. Some of the diodes exhibit photoelectric effects under illumination using monochromatic red light with a wavelength of 670 nm. Maximum quantum efficiency of 53% was obtained under a reverse bias condition from a diode with ZnO film deposited at 480 °C. Measuring photoluminescence, transmittance, sheet resistance from the ZnO films, and characterizing the n-ZnO/p-Si interface with X-ray photoelectron spectroscopy, it is concluded that the diodes with n-ZnO deposited at 480 °C conserve relatively a high film quality and good interface junction to exhibit the best photoelectric property.