不同晶向SrTiO3上外延GaAs薄膜的光谱研究

利用MBE生长技术，成功地在不同晶向SrTiO3(100)(111)(110)衬底上生长了GaAs薄膜，利用显微Raman和荧光光谱（PL）对此进行了研究。实验结果表明，在不同晶向SrTiO3上生长的GaAs薄膜有不同的晶向和应力状态。荧光光谱（PL）研究表明在SrTiO3(100)(111)晶面上生长的GaAs薄膜的PL峰发生明显的蓝移。研究表明在SrTiO3(110)面上生长的GaAs薄膜和体单晶基本上一致，有更好的光学质量。

Optical Studies of the GaAs Films on SrTiO3 Substrates with Different Orientation

In resent years there has been great interest in combining ferroelectric thin films with semiconductor materials.If integration between ferroelectric materials and semiconductor materials can be achieved directly in epitaxial growth,it would open possibilities to explore new applications and new physical phenomena. This paper reports the molecular beam epitaxy(MBE)growth of the GaAs films on the SrTiO 3 substrates with different orientations ((100),(110) and (111)).Micro Raman and photoluminescence(PL) measurements are used to detect the optical properties of these new kinds of heterojunction structures.Two Raman peaks near to 269 and 292cm -1 have been observed which corresponding to the TO and LO phonons of the GaAs single crystal.These show that the GaAs films are well crystallized.Micro Raman studies also show that the rate of the intensity of LO and TO peaks of the GaAs films are different for the different orientations of SrTiO 3.It indicates that the orientations of the GaAs films are different. PL studies show the intensity of the PL peak of GaAs on (100) and (111) SrTiO 3 are quite weak,and large blue shifts (more than 10meV) are observed.These are caused by the large difference of surface lattice periodicity and crystal structure between GaAs and SrTiO 3.The intensity and the position of the PL peak of GaAs film on (110) SrTiO 3 are similar to that of single crystal film.These results show the optical quality of the GaAs film on (110) SrTiO 3 is much better and can compared with that of single crystal film.