[18a-C102-1~11] 6.3 Oxide electronics

[18a-C102-1] Estimation of band-edge fluctuation from temperature dependence on photo-current decay in polycrystalline ZnO thin films

〇(M1)Katsuyoshi Tasaki^1,2, Worasawat Suchada^1,2, Yoichiro Neo², Yoshinori Hatanaka¹, Hidenori Mimura² (1.Shizuoka Univ., 2.RIE)

Keywords:ZnO thin films, Photoconduction effect, Stretched exponential function

The decay processes in photoconduction by the UV irradiation have been studied in zinc oxide (ZnO) polycrystalline films prepared by the rf magnetron sputtering. Decay responses of photocurrent are described due to a result of band edge fluctuation. In this proposed dispersive diffusion recombination, decay current is represented by a stretched exponential function, and a long-term photocurrent decay suggests that the photo-excited carriers recombine under the band-edge modulations of the conduction and valence bands. Important physical parameters related to the band-edge profiles are given as an activation energy for the recombination. The activation energy and band fluctuation energy are given as 0.08~0.1 eV through experimental data fitting.