作　　者： ;

机构地区： 佛山科学技术学院理学院光电子与物理学系

出　　处： 《材料导报》 2010年第10期14-18,共5页

摘　　要： 研究了生长在GaN/Al2O3模板层上的InGaN合金的微结构形态,并通过Raman光谱测定了InGaN合金的晶相,采用分光镜椭圆测量对InGaN合金的光学带隙进行了研究,分析了InGaN合金带隙产生Stokes偏移的本质及原因。AFM显微图表明生长在GaN/Al2O3模板层上的InGaN合金的微结构晶体质量得到了很好的改善。In-GaN合金的Raman光谱曲线非常微弱,与GaN/Al2O3的Raman光谱曲线几乎完全重叠。通过分光镜椭圆测量可知,InGaN合金的光学带隙Eg随着In含量的增加而减少。InGaN合金在红外区域表现出强烈的光致发光峰,随着Ga含量的增加,光致发光峰表现出较大的蓝移即Stokes偏移。在InGaN合金的中间In组分附近Stokes偏移达到最大值。产生Stokes偏移的主要原因是InN在GaN中具有较低的混溶性。Stokes偏移也可归结为InGaN合金中存在局域态,InGaN合金中载流子的局域化程度越高,Stokes偏移就越大。 The microstructure shape of InGaN alloys grown on GaN/Al2O3 template is studied, and the crystal appearance of InGaN alloys is measured by Raman spectrum, and the optical band-gap of InGaN alloys is researched by spectroscopic ellipse measurement. The essence and reason of producing the Stokes shift in InGaN alloys band-gap are analyzed. The AFM micrographs show that the microstructure crystal quality of InGaN alloys grown on GaN/Al2O3 template is improved a lot. The Raman spectrum curve of InGaN alloys is very weak, which is nearly overlapped with that of GaN/Al2O3. The optical band-gap Eg in InGaN alloys decreases with In content increasing by SE measurement. The strong PL peaks in InGaN alloys appear in infrared region, and the PL peaks show a bigger blue-shift with Ga content increasing, this shift is called the Stokes shift. The Stokes shift can achieve maximum near middle In content of InGaN alloys. Nevertheless, the Stokes shift is chiefly produced for InN has very low mixability in GaN. The Stokes shift can also come down to the existence of local states in InGaN alloys. The higher of carries localization degree, the bigger of Stokes shift.

关 键 词： 材料 光学特征 光致发光 偏移

领　　域： [电子电信]