Applied Science and Convergence Technology 2010; 19(3): 211-216
Published online May 1, 2010
Copyright © The Korean Vacuum Society.
Hee Yeon Kim,H. J. OH,S. W. Ahn,Mee-Yi Ryu,J. Y. Lim,S. H. Shin,S. Y. Kim,J. D. Song
The luminescence properties of In0.5Ga0.5As/In0.5Al0.5As multiple quantum wells (MQWs) grown on In0.5Al0.5As buffer layers have been studied by using photoluminescence (PL) and time-resolved PL measurements. A 1-㎛ thick In0.5Al0.5As buffer layers were deposited on a 500 ㎚ thick GaAs layer, followed by the deposition of the InGaAs/InAlAs MQWs. In order to investigate the effects of InAlAs buffer layer on the optical properties of the MQWs, four different temperature sequences are used for the growth of InAlAs buffer layer. The growth temperature for InAlAs buffer layer was varied from 320℃ to 580℃. The MQWs consist of three In0.5Ga0.5As wells with different well thicknesses (2.5 ㎚, 4.0 ㎚, and 6.0 ㎚ thick) and 10 ㎚ thick In0.5Al0.5As barriers. The PL spectra from the MQWs with InAlAs layer grown at lower temperature range (320-480℃) showed strong peaks from 4 ㎚ QW and 6 ㎚ QW. However, for the MQWs with InAlAs buffer grown at higher temperature range (320-580℃), the PL spectra only showed a strong peak from 6 ㎚ QW. The strongest PL intensity was obtained from the MQWs with InAlAs layer grown at the fixed temperature of 480℃, while the MQWs with buffer layer grown at higher temperature from 530℃ to 580℃ showed the weakest PL intensity. From the emission wavelength dependence of PL decay times, the fast and slow decay times may be related to the recombination of carriers in the 4 ㎚ QW and 6 ㎚ QW, respectively. These results indicated that the growth temperatures of InAlAs layer affect the structural and optical properties of the MQWs.
Keywords: 포토루미네션스,시간분해 포토루미네션스,분자선 에피택시,InAlAs,InGaAs/InAlAs MQWs,Photoluminescence,Time-resolved photoluminescence,Metamorphic,Molecular beam epitaxy