MOCVD生长的InGaN合金的性质

对使用MOCVD方法在蓝宝石衬底上生长的典型InGaN样品进行了光致发光(PL)、霍耳(Hall)及扫描电镜(SEM)测量．结果表明:适当的生长温度(750℃)提高了样品中In的含量和PL强度。当Ⅴ/Ⅲ族比率大约5000时，750℃生长的样品背景载流子浓度约为2.21×1018cm-3,In含量约为11.54%．其室温394nm的带边峰,半高宽约为116meV,束缚能约为32.4meV,可能与束缚激子发光相关．该样品禁带宽度随温度变化的温度系数α(dE/dT)约为0.56×10-3eV/K．较高温度(800℃和900℃)生长的样品In含量较低,PL强度较弱,且在样品表面析出了金属In滴．

Properties of InGaN Layers Grown on Sapphire Substrates by MOCVD

InGaN films of various compositions grown by MOCVD using PL, Halland SEM techniques have been analysed. When the Ⅴ/Ⅲ ratio is equal to 5000, the temperature of 750℃ is suitable for the growth of InGaN samples. Under these specific conditions, the electron concentration is about 2.21×1018cm-3 and In content about 11.54%. The wavelength of the near band-gap edge peak is 394nm at 295K and its full width of half maximum (FWHM) is about 116meV. According to the relations between the wavelength and the intensity of the near-band-gap-edge peak，at the growth temperature of 750℃,it can be obtained the temperature coefficient α(dE/dT) of the InGaN sample is 0.56×10-3eV/K and the binding energy of the near-band-gap-edge peak is 32.4 meV.At higher growth temperatures (800℃ and 900℃) ，the In content and the PL intensity of InGaN sample will decrease. And the meatl particles of In can be observed on the surface of the sample.