MOCVD生长的InGaN合金的发光特性  

Optical Properties of InGaN Film Grown by MOCVD

作　　者：竹有章[1] 陈光德[1] 谢伦军[1] 唐远河[1] 邱复生[1] 

机构地区：[1]西安交通大学理学院应用物理系

出　　处：《发光学报》2005年第5期602-606,共5页Chinese Journal of Luminescence

基　　金：国家自然科学基金资助项目(10474078)

摘　　要：研究了用金属有机化学气相沉积(MOCVD)法在蓝宝石基底上生长的InGaN样品的发光特性。样品XRD谱中存在InGaN、In、InN相,表明样品中存在相分离;透射谱能看到由于F-P腔调制引起的震荡;相对氙灯激发发光谱,激光激发的发光谱其发光峰位置发生蓝移。由于样品上下表面形成F-P腔,对发光谱产生强烈的调制,在较高强度激发下,在室温下带边峰分成三个峰,其中波长较短的两个发光峰表现出相同的特征,其发光机制可能为以In量子点为局域中心的局域化激子复合发光,而波长较长的发光峰,是一个超线性受激发光峰,其发光机制可能是电子-空穴等离子的散射。不同温度的PL谱表明两个主要的发光峰表现出不同的温度特征,利用F-P干涉理论分析可知,当温度高于120 K后样品折射率随着温度的升高而增大。Ⅲ-nitride semiconductors hare attracted mach attention recently due to their applications in eletronic and optoelectronic such as high bright blue and green light emitting diodes （LEDs） and laser diodes （LDs）. InGaN has been used as active layers for most nitride LEDs. However, the luminescence mechanism in InGaN alloys is still in question, especially how the structural and compositional homogeneities in the alloy affect on the optical properties of the devices. Photoluminescence properties of InGaN film grown on sapphire substrates by metal organic chemical vapor deposition（MOCVD） were experimentally investigated by means of X-ray diffraction（XRD）, transmission spectra and PL spectrum. The peaks of InGaN, InN and In were observed on XRD spectrum. It might be evidence of phase separation and In quantum dots in the sample. A clear oscillation could be observed on transmission spectra of the sample. As PL spectra excited by xenon lamp, a blue shift of emission peak position was observed. Additionally, when the optical excitation density was increased, the emission peak will split to three peeks. That could be explained by interference due to F-P cavity arising from surface of sample. The excitation density dependence of PL intensity shows that these emission peaks have different character, the two high energy peak might be originated from local exciton recombination, and the low energy peak is stimulated emission peak, and might be originated from electron-hole plasma （EHP） recombination. Temperature dependence of PL spectra was investigated, peak positions of high energy peak changed with ＂S-shape＂ by increasing of temperature, and it is different from character of the low energy peak. The red shift of the peak positions as increase temperature indicated the increasing of refract index.

关 键 词：INGAN 光致发光 F—P腔 受激辐射 折射率 

分 类 号：O472.3[理学—半导体物理] O482.31[理学—物理]