Li을 첨가한 ZnO 세라믹의 유전특성에 관한 연구

Abstract

Dielectric properties of Li-doped ZnO ceramics

Lee Joohyun

Department of Physics, Graduate School Pukyong National University

Abstract

In the new 21st century, the leaders of the industries, semiconductor, and IT industries prominently developed. On the other hand, the IT industry largely depends on the exploitations of the semiconductor. ZnO has the physical and chemical characters which are suitable for displays and telecommunication industry. So ZnO is a meterial which has very high research value. It has been investigated to realize ZnO based photoelectric devices which are ultraviolet light-emitting diodes, photodetector, solar cells and so on. It is necessary both n-type and p-type ZnO. The n-type ZnO can be achieved by doping with Al, Ga or In. But p-type ZnO is difficult because of deep acceptor level, low solubility of acceptor dopants and its self compensation effects. Group I-elements are considered to be good dopants. Especially Li has the shallowest value, the acceptor level of Li substituted Zn is 0.09eV, among the energy level of acceptor dopants. In this study, we have prepared Li doped ZnO ceramics. The effect of Li doped on the crystal structure, dielectric and ferroelectric properties were investigated by XRD, FE-SEM, dielectric constant and ferroelectric P-E hysteresis loops measurements. Through many substantial tests, we have concluded the following; According to the result of XRD, Li are doped into ZnO. successfully and the impurities affact to the structure of ZnO. We can identify most compact crystalline on Li0.12Zn0.88O FE-SEM image. The dielectric constant of LixZn1-xO(x = 0.05, 0.08, 0.10, 0.12, 0.15) ceramics is involved with the temperature and the frequencies. The LixZn1-xO ceramics specimens show phase change around the temperature of 85∼90℃. And the dielectric constant by frequencies is lower depending on Li concentration. Li0.12Zn0.88O show ferroelectric hysteresis loop with largest remanent polarization(Pr) of 0.071μC/cm2