蓝宝石R面上ZnO薄膜的NH3掺杂研究

以NH₃为掺杂源,利用金属有机化学气相沉积(MOCVD)系统在蓝宝石R面上生长出掺氮ZnO薄膜。通过XRD,SEM测量优化了其生长参数,在610℃和在80sccm的NH₃流量下生长出了〈1120〉单一取向的ZnO薄膜。经Hall电阻率测量,得知该薄膜呈现弱p型或高电阻率,并对其光电子能谱进行了研究。

Study on NH3 Doping in ZnO Film Grown on R-plane of Sapphire Substrate

ZnO thin films doped with NH₃ have been grown on R-plane sapphire substrate by MOCVD and the growth parameters have been optimized by XRD and SEM method. The only 〈1120〉oriented ZnO thin film has been obtained in 610℃ and 80sccm NH₃ flux, and the FWHM of 〈1120〉 plane X-ray diffraction peak is only 0.50°. At the same time, the samples’SEM images show that the surface of the sample with 80sccm NH₃ is the most smooth, which may be related to the amount of hydrogen atom in the sample. The electronics properties of the samples were determined by Hall method. The results show that the resistivity of the film with 80sccm NH₃ is up to 10⁸Ω·cm, and the film with 50sccm NH₃ shows low p-type. In order to investigate the nitrogen atom form in the samples, X-ray photoelectron spectra of the samples have been studied. The results show that the N1s photoelectron comes from N^3- for the sample with 50sccm NH₃. For the sample with 80sccm and 110sccm NH₃, the N1s photoelectron comes from NH^2- and NH₂^-, respectively. This implies that some hydrogen atoms were introduced into the samples with increase of NH₃ flux. All above indicate that high quality ZnO thin film doped with NH₃ has been obtained on R-plane sapphire substrate. Furthermore, some films show not only high resistivity but also low p-type, which is good for the application of ZnO film. 