射频磁控共溅射GaAs/SiO_2纳米颗粒镶嵌薄膜的光学性质  

Optical properties of GaAs nano-granular embedded in SiO_2 matrix prepared by RF magnetron cosputtering technique

作　　者：丁瑞钦[1] 王浩[1] 于英敏[1] 王宁娟[1] 佘卫龙[2] 李润华[2] 丘志仁[2] 罗莉[2] 蔡志岗[2] W Y Cheung S P Wong 

机构地区：[1]五邑大学薄膜与纳米材料研究所,江门529020 [2]中山大学超快速激光光谱国家重点实验室,广州510275 [3]香港中文大学电子工程系暨材料科技研究中心

出　　处：《物理学报》2002年第4期882-888,共7页Acta Physica Sinica

基　　金：国家自然科学基金 (批准号 :6 980 6 0 0 8);广东省自然科学基金 (批准号 :970 716 );中山大学超快速激光光谱国家重点实验室开放课题(批准号 :1999)资助的课题~~

摘　　要：应用射频磁控共溅射方法和真空退火方法制备了GaAs SiO2 纳米颗粒镶嵌薄膜 .X射线衍射实验结果表明 ,经高温退火的薄膜中形成了面心立方闪锌矿结构的GaAs纳米晶粒 ,晶粒平均直径为 1.5— 3.2nm .吸收光谱展示了由于强量子限域引起的 1.5— 2eV的吸收边蓝移 .室温光致荧光 (PL)光谱显示了电子 重空穴激子与电子 劈裂空穴激子的近紫外和紫外双PL谱峰以及深俘获态的PL谱峰 .对实验吸收边蓝移量与有效质量模型的蓝移量的悬殊差别、俘获态PL谱的形成以及PL谱线的特征作了解释 .应用激光Z扫描技术测量了退火温度为 5 0 0℃的复合膜在非共振条件下的光学非线性 ,结果表明 ,复合膜的非线性折射率系数和非线性吸收系数都比块材GaAs相应的系数增大了 5个数量级 .Films of GaAs nano-grains embedded in a SiO2 matrix have been prepared by radio frequency magnetron co-sputterring technique followed by vacuum annealing. Results of X-ray diffraction experiments suggest the existence of GaAs nanocrystals with fee structure in the SiO2 matrix by annealing at higher temperatures, and the average diameter varies from 1.5 to 3.2nm. Very large blueshifts of absorption edge ranging from 1.5 to 2.0 eV with respect to that of bulk GaAs exhibit in the absorption spectra. Room temperature photoluminescence spectra show a double-peak ultraviolet photoluminescence which originates from the radiative recombination of the quantum confined electron-heavy hole excitons and electron-split-off hole excitons and the peaks in the visual region correspond to the deep traps far below the band edge. The great discrepancy between the absorption blue shifts from experiment and effective mass model as well as the formation and characteristics of photoluminescence spectra are explained. Nonlinear optical property of the film annealed at 500degreesC has been measured by laser Z-scan technique, and the result shows that both the nonlinear refractive index and absorption coefficient of the composite film under non-resonant condition are all 5 orders of magnitude greater than those of the bulk GaAs, and these mainly result from the strong quantum confinement.

关 键 词：射频磁控共溅射 GaAs/SiO2 纳米颗粒镶嵌薄膜 光谱 激光Z扫描 光学性质 砷化镓 二氧化硅 半导体纳米材料 

分 类 号：O484.41[理学—固体物理] TB383[理学—物理]