Investigations of linear and nonlinear optical properties of transparent ZnO thin films grown by sol-gel method
W. Bala1‘2 K. Paprocki1, M. Kuczkowska1, K. Fabisiak1, A. Zawadzka2, P. Płóciennik2, J. Szatkowski2, K. Banach2, J. Luc3, B. Sahraoui3,
1lnstitute ofPhysics, Kazimierz Wielki University, Powstańców Wielkopolskich 2, PL 85-072 Bydgoszcz, Poland wbala@fizyka, umk.pl
Institute ofPhysics, N. Copernicus University, Grudziądzka 5/7, PL 87-100 Toruń, Poland
3Laboratory POMA, UMR CNRS 6136, University ofAngers, 2 Boulevard Lavoisier, 49045 Angers, France,
Zinc oxide (ZnO) thin films have attracted significant attention as a wide gap semiconductor due to their wide rangę of electrical and optical properties. It is a wide-bandgap oxide semiconductor with a direct energy gap of about 3.37eV and a larger exciton binding energy (60 meV), which assures more efficient exciton emissions at higher temperatures. The thin layers of ZnO have potential application in electronics, optoelectronics and information technology devices including displays, sołar cells and sensors [1,2].
The optical properties of ZnO thin films grown by sol-gel method on silica glass were studied using second and third harmonie generation and photoluminescence measurements, respectively. The structural properties of the ZnO thin films were carried out using x-ray method. The effects of the thickness variation and annealing temperaturę on the crystallinity parameters were observed. The strong dependence of the films structure, the crystalline ąuality and the optical properties was also noticed. We observed that the annealing of ZnO films leads to inerease of the crystallite size and this cause to considerable rise of the photoluminescence intensity. The photoluminescence spectra were measured at the temperaturę rangę from 13 K to 350 K. We observed the changing of the near band edge (NBE) emission with temperaturę.
The very high conversion efficiency to the second and third harmonie radiations are achieved for Q-switched Nd:YAG laser working at 1064 nm.
[1] S. Bandyopadhyay, G.K. Paul, S.K. Sen, Sol. Energy Mater. Sol. Cells 71 (2002) 103. [2] Y. Natsume, H. Sakata, Thin Solid Films 372 (2000) 30.
