Abstract
The properties of ZnO are of great interest because it is a wide and direct band gap material. With such a band structure, it is believed that ZnO is a potential material for fabricating UV optoelectronic devices. Since the properties of semiconductors are highly related to the behaviours of the defects inside, the first step is to understand the characters of defects in ZnO.
In the old days, the activation energy and cross sectional area of a defect can be determined electrically by DLTS technique. This measurement is usually done by applying the double box-car averaging method. The advantage of this method is that its requirements on data acquisition and storage are comparatively low. Recent improvements in computer speed and noise elimination algorithm allow the development of a high resolution Laplace-DLTS system. With such an improvement in resolving power, more details about defects with similar energy level can be studied.
In this seminar, the basic principles of both DLTS and L-DLTS will be reviewed. We will also demonstrate the improvement in resolution of L-DLTS technique and present current results of L-DLTS measurements on n-type ZnO thin film.