GaN薄膜的制备及其振动光谱的密度泛函理论研究

以氧化镓为镓源, 用溶胶-凝胶和高温氨化二步法, 在Si(111)衬底上制备出GaN薄膜. X射线衍射(XRD)分析表明制备的GaN薄膜是六角纤锌矿结构; 扫描电子显微镜(SEM)图片显示GaN晶粒的尺寸<100nm; 薄膜的红外光谱(FTIR)中有GaN的E1 (TO)声子模式. 用密度泛函理论(DFT)计算了氮化镓小团簇的振动频率. 结果表明: 富镓氮化镓团簇的振动频率在六方晶系纤锌矿结构GaN的光学声子峰值附近; 富氮氮化镓团簇中的N--N键的振动频率为2200cm^-1. 用氮化镓团簇的频谱对所制薄膜的红外光谱作了进一步分析.

Preparation of GaN Film and Investigation of Vibrational Spectrum of GaN by DFT

Using Ga₂O₃ as Ga source, the GaN films are successfully deposited on Si (111) substrates by two-step method of sol-gel and high nitridation temperature technique. The as-prepared films were confirmed as single crystalline GaN with wurtzite structure by X-ray diffraction (XRD). The dimension of GaN crystal particulates is smaller than 100nm under the observation of scanning electron microscope (SEM). Moreover, E1 (TO) vibrational mode of GaN are surveyed in IR spectrum of the GaN films. Vibrational frequency of GaN small clusters is calculated using density functional theory (DFT). The results show that the vibrational frequencies of the Ga reached clusters are close to the peaks of the phonon vibration modes of the wurtzite structure GaN, and 2200cm^-1 is an intensive vibrational frequency of N--N bond stretch in N reached GaN. FTIR of the sample are analyzed in further.