原位氧化Zn_3N_2制备p型ZnO薄膜的性能研究

Preparation of p-type ZnO thin films by in situ oxidation of Zn_3N_2

采用射频反应溅射法在玻璃衬底上制备Zn3N2薄膜,然后向真空室中通入纯氧气进行热氧化制备ZnO薄膜.利用X射线衍射、扫描电子显微镜、霍尔效应测量、透射光谱和光致发光光谱等表征技术,研究了氧化温度和氧化时间对ZnO薄膜的结晶质量、电学性质和光学性能的影响.研究结果显示,450℃下氧化2h后的样品中除含有ZnO外,还有Zn3N2成分,500℃下氧化2h可以制备出电阻率为0.7Ωcm,空穴载流子浓度为1017cm-3,空穴迁移率为0.9cm2/Vs的具有c轴择优取向的p型ZnO薄膜.此时的ZnO薄膜具有良好的光学特性,紫外可见光范围内透过率为85%,处于紫外区域的激子复合产生的发光峰很强,且半高宽较窄,而处于可见光部分来自于深能级发射的绿色发光峰很弱.这种工艺制备的ZnO薄膜质量较好,有利于实现在短波长光电器件方面的应用.

Low resistance p-type ZnO thin films were prepared by in situ oxidation of Zn3 N2 films which were deposited by reactive radio-frequency magnetron sputtering of zinc in Ar-N2 mixture atmosphere. The effects of oxidation temperature and time on structural, electronic and optical properties of the samples were investigated by X-ray diffraction, scanning electron microscopy, Hall-effect measurements, transmittance spectra and photoluminescence spectra. It was found that the sample oxidized at 450℃ contains Zn2N3 besides ZnO. The sample oxidized at 500℃ for 2 h had good properties of low resistance （0.7 Ωcm）, good transmittance rate （ above 85 % ）, predominant excitonic ultraviolet emission with narrow full width at half maximum and weak deep level visible emission. The low resistance p-type ZnO films could be used in short wavelength industrial application.