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采用有机金属化学气相沉积(MOCVD)在r面蓝宝石衬底上生长a-AlGaN外延膜,研究了AlN插入层对a-AlGaN外延膜的应力和光学性质的影响。根据高分辨X射线衍射(HRXRD)技术和扫描电子显微镜(SEM)我们可以得到,AlN插入层有效地提高了a-AlGaN外延膜的晶体质量并减小了外延膜材料结构的各向异性。由拉曼光谱得到AlN插入层的引入减小了a-AlGaN外延膜的面内压应力,其原因是AlN插入层可以当作衬底有效的调制与减小a-AlGaN外延膜与r面蓝宝石衬底的晶格失配,从而使a-AlGaN的面内应力得到适当释放。对室温下的光致发光进行测量得到AlN插入层的使用使近带边发射峰(NBE)发生了红移,这可能是由于残余应力的减小引起。
A-AlGaN epitaxial films were grown on r-plane sapphire substrates by metal organic chemical vapor deposition (MOCVD). The effects of AlN insertion layer on the stress and optical properties of a-AlGaN epitaxial films were investigated. According to high resolution X-ray diffraction (HRXRD) and scanning electron microscopy (SEM), we can get that the AlN insertion layer effectively improves the crystal quality of the a-AlGaN epitaxial film and reduces the anisotropy of the epitaxial film material structure. The introduction of AlN insertion layer by Raman spectroscopy reduces the in-plane compressive stress of the a-AlGaN epitaxial film because the AlN insertion layer can serve as a substrate for effectively modulating and reducing the growth of the a-AlGaN epitaxial film and the r-plane sapphire The lattice mismatch of the substrate, so that the a-AlGaN in-plane stress is properly released. Measurement of photoluminescence at room temperature. The use of AlN intercalated layers caused a red shift in the near-band edge emission peak (NBE), which may be due to the reduction of residual stress.