Photoconductivities in: M-plane and c-plane ZnO epitaxial films grown by chemical vapor deposition on LiGaO2 substrates: A comparative study
Journal
RSC Advances
Journal Volume
6
Journal Issue
89
Pages
86095-86100
Date Issued
2016
Author(s)
Abstract
The photoconduction properties of (non-polar) m-plane and (polar) c-plane ZnO thin films epitaxially grown on relatively lattice-matched LiGaO2 substrates by chemical vapor deposition have been investigated and compared. Structural and photoluminescence characterizations indicate that the c-plane ZnO films possess higher crystallinity than the m-plane ZnO films. Owing to their superior crystallinity and lower dark current, the c-plane ZnO films exhibit significantly higher optimal sensitivity (S = 4650) to ultraviolet light than the m-plane ZnO films (S = 10). However, in terms of photocurrent generation efficiency, the m-plane ZnO films exhibit over one order of magnitude higher responsivity (R = 0.05-3.2 A W-1) than the c-plane ZnO films (R = 0.009-0.035 A W-1) in the light intensity range 1.6-320 W m-2. The probable mechanisms causing the aforementioned differences based on surface-dominant photoconduction and bulk-dominant structural and photoluminescence properties are also discussed.
Publisher
Royal Society of Chemistry
Type
journal article