InN分凝的InGaN薄膜的光致发光与吸收谱(英文)

Photoluminescence and Absorption in InGaN Filmswith InN Segregation

我们用低压MOCVD在蓝宝石衬底生长了InGaN/GaN外延层。用X射线衍射 (XRD) ,光致发光谱(PL) ,光吸收谱等测量手段 ,研究了InGaN的辐射发光机制。In组分利用Vegard定理和XRD测量得到。我们发现随着In组分的增加 ,在光吸收谱上发现吸收边的红移和较宽的Urbach带尾 ;PL谱中低能端的发射渐渐成为主导 ,并且在PL激发谱中InGaN峰也变宽。我们认为压电效应改变了InGaN的能带结构 ,从而影响了光学吸收特性。而在InN量子点中的辐射复合则是InGaN层发光的起源。

InGaN/GaN layers have been grown under low pressure by metalorganic vapor phase epitaxy on sapphire substrate. X ray diffraction (XRD), photoluminescence (PL) , absorption measurements have been applied to study the radiative recombination mechanisms in the samples. The In composition is determined by XRD measurement using Vegard’s law. With In composition increasing, a red shift of absorption e dge and a broad Urbach tail in absorption spectra are observed. Low energy emiss ion is dominant in PL spectra as well, and InGaN peaks in PL excitation spectra are broadened too. We suggest that the piezoelectric effect changed the band str uctures of InGaN, which affects on the optical absorption behavior. Radiative re combination in the InN quantum dots are attributed to the origin of emission of InGaN layer.