用射频溅射方法制备的多晶ZnO薄膜的光响应与其结构变化

PHOTORESPONSE OF POLYCRYSTALLINE ZnO FILMS DEPOSITED BY RF SPUTTERING AND THEIR STRUCTURAL RELAXATION

用射频溅射方法在较高氧压下沉积的多晶的ZnO薄膜,其光响应主要由两部分组成:第一部分来源于膜内晶粒界面所吸附氧原子的光脱附,该部分光响应可使膜的电导率增加两个数量级且响应速度较快;第二部分来源于薄膜表面所吸附氧原子的光脱附,此光响应可使膜的电导率增加4一5个数量级,但响应速度非常缓慢.两部分光响应都来自薄膜的结构变化,膜的结构变化与膜所处环境中气体的种类,压强以及膜的温度有关.

The photoresponse of polycrystalline ZnO films deposited by r. f. sputtering at a high oxygen pressure consists of two parts. The first part of photoresponse originates from photodesorption of adsorbed oxygen on the interface of crystallites of the ZnO films. This part of photoresponse increases the conductivity of the films by 2 orders of magnitude and the response speed is relatively fast. The second part of photoresponse is due to photodesorption of adsorbed oxygen on the surface of the films. This photoresponse increases the conductivity of the films by 4-5 orders of magnitude and the response speed is very slow, these two parts of photorespon-seall originate from structural changes of the films and the structural changes depend on ambient gases, gas pressure and temperature of the samples.