磁控溅射方法生长的氮氧锌薄膜的光学特性

Optical Properties of Nitride Zinc Oxide Prepared by Radio Frequency Sputtering

氧化锌(ZnO)是一种具有六方结构的宽禁带Ⅱ Ⅵ族半导体材料,室温下能带带隙Eg为3 37eV。由于氧化锌在室温条件下具有较高的激子束缚能(60meV),保证了其在室温下较强的激子发光。此外氧化锌还具有较高的热稳定性和抗化学腐蚀特性,因而被认为是制作紫外半导体激光器的合适材料。自1997年首次发现ZnO室温紫外受激发射以来,ZnO已成为继GaN之后紫外发射材料的又一研究热点。但是,目前对于p型氧化锌及其发光器件的研究仍处于探索阶段,对其光电特性的研究仍需要更多投入。本文利用磁控溅射方法制备出氮氧锌薄膜样品,并通过在氧气气氛下退火处理,改变薄膜样品中氮的含量。通过X射线衍射谱、X射线光电子能谱、光致发光谱及喇曼光谱的测试,研究了氮在氧化锌薄膜中的含量变化以及氮对氧化锌薄膜的结构和光学特性的影响。

ZnO is an ntype semiconductor having a hexagonal wurtzite structure. Because its exciton bonding energy is as high as 60meV, ZnO exhibits good piezoelectric, photoelectric and optical properties at room temperature, and might be a good candidate for laser and electroluminescence device. In addition, the melting point of ZnO is high enough to ensure its thermal stability. Since the discovery of the laser of ZnO in ultraviolet light region in 1997, ZnO has become a new hotspot in the research of the ultraviolet light emission material. But for the existence of some native defects in ZnO, generally, ZnO is a ntype semiconductor material. By this time, the research of ptype ZnO material still needs more work. According to previous reports, nitrogen is a promising candidate of dopant for the fabrication of ptype ZnO, so a lot of researchers make attention of the doping of nitrogen into ZnO.Nitride zinc oxide thin films were fabricated by rf. sputtering technique, and the concentration of nitrogen in films was changed by a series of annealing process in oxygen ambient in this letter. The annealing temperature is ranged from 300 to 1 000℃. After the annealing process, Xray diffraction spectrum, Xray photoelectron spectrum, Photoluminescence spectrum and Raman scattering spectrum were used to investigate the change of the crystal structure and the optical properties of the films and the effect of the nitrogen doping was discussed.