摘要
利用深能级瞬态谱 (DLTS)和光致发光谱 (PL) ,研究了ZnO/p Si异质结的两种不同温度 (85 0℃ ,10 0 0℃ )退火下的深能级中心。发现 85 0℃退火的样品存在 3个明显的深中心 ,分别为E1=Ev+0 2 1eV ,E2=Ev+0 44eV ,E3=Ev+0 71eV ;而 10 0 0℃退火样品仅存在一个E1=Ev+0 2 1eV的中心 ,且其隙态密度要比 85 0℃退火的大。同时 ,测量了两个样品的PL谱。发现 10 0 0℃退火可消除一些影响发光强度的深能级 ,对改善晶格结构 ,提高样品的发光强度有利。
The technology of deep level transient spectroscopy (DLTS) develops from the technology of measuring transient capacitance. Through the temperature scanning, it can rapidly,exactly describe the deep levels of the sample. And it has wide measuring range. So it has been becoming the popular measurement to study the deep level of the semiconductor. Zinc oxide is a self activated crystal with hexagonal wurtzite structure and has a gap of 3 3eV at room temperature.ZnO phosphor powders have been studied for several decades. Recently, ZnO films have attracted attention due to their wide applications in photoelectric materials such as surface acoustic wave guide, piezoelectric materials, transparent electrodes for some solar cells, and as a buffer layer for GaN. As most efforts focus on short wavelength semiconductor materials, stimulated and spontaneous ultraviolet emissions of ZnO thin films have been found. Comparing to the semiconductors used in conventional lasers, the UV emission of ZnO films has shorter wavelength. If a practical emitting device with short wavelength made by ZnO films could be fabricated, it must have exciting applications in compact disk recorder and other photoelectronics areas. In order to know the mechanism of its photoluminescence, the research in the properties of ZnO films is therefore important. In this article, we use deep level transient spectroscopy (DLTS) to study the ZnO/p Si heterostructure which was treated by two different temperatures (850℃, 1 000℃ ) and to find its relationship to the photoluminescence .The results showed that the sample 1 # (850℃ treated) has three obvious deep levels ( E 1 , E 2, E 3) and the sample 2 # ( 1 000℃ treated) has only E 1 level. But the density of this level is higher than that of sample 1 #. At the same time, the photoluminescence spectra of the samples were also measured . It is found that the sample 2 # has higher density of photoluminescence because it has less levels and higher density of the level. Through the higher temperature ( 1 000℃ ) treatment, some defect levels which affect the photoluminescence disappeared, and the crystal lattice become more integrated. So the treatment temperature of 1 000℃ is efficient to improve the density of the photoluminescence of ZnO.
出处
《发光学报》
EI
CAS
CSCD
北大核心
2001年第3期218-222,共5页
Chinese Journal of Luminescence
基金
国家自然科学基金资助项目 ( 5 9872 0 37)
安徽省自然科学基金资助项目 ( 986 415 5 0 )
