c-AlN/TiN/Si(100)异质结构的显微组织及光学性能

Microstructure and Optical Properties of c-AlN/TiN/Si(100) Heterostructure

立方氮化铝(c-AlN)以其优异的性能成为发光二极管、激光二极管等光电子器件的理想材料。采用激光分子束外延法制备了c-AlN/TiN/Si(100)异质结构,研究了它的显微组织和光学性能。结果表明:AlN薄膜和TiN缓冲层呈立方岩盐矿结构的(200)面择优取向;c-AlN薄膜、TiN缓冲层和Si衬底的界面清晰,不存在第二相,但错配应力使得界面处存在一定的缺陷;c-AlN薄膜的光致发光谱分别在376,520,750 nm处有3个发光中心;376 nm处的发光峰与氮空位(VN)和氧杂质(ON)有关,520 nm处的发光峰与Al空位(VAl)和ON的复合有关,而750 nm处的发光峰可归因于VAl和价带之间的辐射复合;c-AlN薄膜的电致发光中心在580 nm附近,也属于c-AlN的深能级缺陷发光。

Owing to its excellent properties,cubic aluminum nitride(c-AlN)is an ideal material for optoelectronic devices such as light-emitting diodes and laser diodes.In this study,the c-AlN/TiN/Si(100)heterostructure is deposited using the laser molecular beam epitaxy technique,and its microstructure and optical properties are investigated.The experimental results show that the AlN film and the TiN buffer layer both show a(200)preferred orientation of cubic rock-salt structure.The interfaces between the c-AlN film,TiN buffer layer,and Si substrate are clear;a second phase is not observed.However,there are certain defects at the interface owing to mismatched stress.The photoluminescence spectrum of c-AlN film exhibits three emission peaks at approximately 376,520,and 750 nm.The emission peak at 376 nm is related to nitrogen vacancy(VN)and oxygen impurity(ON).The emission peak at 520 nm is related to the recombination of Al vacancies(VAl)and ON.The emission peak at 750 nm can be attributed to the radiation recombination between VAl and the valence band.The electroluminescence emission peak of c-AlN film is approximately at 580 nm,and it is attributed to a deep-level defect emission.