【摘要】 利用MOCVD方法生长了高质量的ZnO薄膜材料,分别通过N₂和NH₃对c面和R面蓝宝石衬底上生长的ZnO薄膜材料进行了掺杂行为研究。掺N₂时,X射线衍射半峰全宽仅为0.148°,室温光荧光发光峰位于3.29 eV,半峰全宽～100 meV,电阻率由0.65Ω·cm增大到5×10⁴Ω·cm。掺NH₃时,X射线衍射峰半峰全宽0.50°,样品为弱p型,电阻率为102 Ω·cm,载流于浓度为1.69×10¹⁶cm^-3。同时我们还观察到弱p型材料很容易退化成n型高阻材料。更多还原

【Abstract】 ZnO is a multi-function direct wide-band semiconductor material with wurtzite structure. It has potentialapplications in varistors, phosphors, transparent electrode, optoelectronic devices, blue-purple light devices. n-type low resistivity ZnO is easy to obtain. However, the difficulty of high resistivity ZnO and p type ZnO must beresolved for the purpose of fabricating practical ZnO devices. Although many research groups are working on it, p-type ZnO problem has never been figured out. N is an effective p-type dopant for Ⅱ-Ⅵ group compounds. Thereare two effects when N is doped in ZnO thin films: providing a shadow acceptor energy level and decreasing concen-tration of Zn_i atoms by combining with ZnO. Thus, it is possible to obtain high resistivity and p-type ZnO by dopingN atoms in ZnO. There has two kinds of N source, N₂ and NH₃. In this paper, the behaviors of N₂ and NH₃ doped in ZnO thin films are investigated. Firstly, N₂ was doped in ZnO thin films grown on c-plane sapphire substrate using plasma assisted MOCVDsystem. Plasma generator of plasma assisted MOCVD system is very efficient to dope N atoms into ZnO films and toobtain high resistivity ZnO thin films. The N₂ doped ZnO films have all of properties of ZnO and show high crystalquality, especially in optical properties, which show light-yellow body color. XRD measurement shows a high inten-sity peak at 2θ=34.6°with a FWHM of 0.148°, which is （002） peak of ZnO. The corresponding value of double-crystal XRD rocking-curve is 0.34°. The emitting peak locates at 3.29 eV in PL spectrum with a FWHM of 100meV. Compared with 0.65Ω·cm of undoped sample, the resistivity increases to 5×10⁴Ω·cm with N₂ doping. Secondly, the behavior of NH₃ doped ZnO grown on R-plane sapphire has been investigated. After optimizedgrowth conditions, the XED result shows a high intensity peak at 2θ=56.30°with a FWHM of 0.50°, which is〈110〉peak of ZnO. The AFM photo shows that the surface of the film is very smooth. The roughness is about 3.01nm. Under different NH₃ flux, the sasple’s, resistivity has different value as well as electrica1 conduction type.The p-type sample was obtained when NH₃ flux is 80 sccm with the resistivity of 102Ω·cm, observed by Hall mea-surement. Finally, we found that the p-type sample has the trend of turning to n-type. This maybe is due to instability ofN - Zn bond in N doped ZnO which is investigated by XPS measurements. Consequently, behavior studies of Ndoping in ZnO are important to achieve high resistivity p-type ZnO thin films. Furthermore, it is maybe possible toobtain better results by annealing samples under protection of N₂ or NH₃.更多还原