摘要
本文报道（0001）晶向蓝宝石衬底上金属有机化学气相淀积（MOCVD）方法生长的单晶六角GaN薄膜室温光学性质．由光吸收谱和488umAr+激光激发的光调制反射光谱（PR）确定的禁带宽度分别为3．39和3．400eV，从光吸收谱得到了GaN薄膜的折射率随光谱能量的变化关系．对PR谱的调制机理进行的分析，发现信号来自缺陷作用下的表面电场调制．应用喇曼光谱研究了GaN薄膜中的声子模，通过对LO声子-等离激元的耦合模散射峰的研究，得到了材料中的载流子浓度和等离激元阻尼常数．
The room temperature optical properties of single crystal hexagonal GaN films on (0001) sapphire substrate grown by metalorganic chemical vapor deposition (MOCVD) are reported. The energy gap of hexagonal GaN is determined as 3. 39 and 3. 400eV by optical transmission and 488um Ar+ laser excited photoreflectance, respectively, and refractive index of GaN film as the function of photon energy is obtained. The possible origin of the PR signal is attributed to the modulation of the surface field and lineshape broadening of defects. Raman scattering spectra are employed to investigate the photon modes of the GaN film. The properties of LO phonon-plasmon coupled modes are further studied, and the carrier concentration and damping constant are determined by line-shape fitting of the coupled modes.
关键词
氮化镓
MOCVD生长
光学性质
Absorption spectroscopy
Chemical vapor deposition
Epitaxial growth
Nitrogen compounds
Optical films
Optical properties
Phonons
