Quantum dot-like effect in InGaAs/GaAs quantum well

¹ Nano Convergence Device Center, Korea Institute of Science and Technology, Seoul 136-791, Republic of Korea
² University of Science and Technology, 113 Gwahangno, Yuseong-gu, Daejeon 305-333, Republic of Korea

^a e-mail: cds_moh@yahoo.com

Received: 8 September 2010
Revised: 18 February 2011
Accepted: 29 March 2011
Published online: 11 August 2011

Abstract

In_0.18 Ga_0.82As/GaAs quantum well sample is prepared by molecular beam epitaxy. The integrated photoluminescence dependence on the excitation power intensity is studied. The critical exciton temperature is found to be around 210 K. The high critical exciton temperature is due to the increased in-plane confinement potential. To understand the photoluminescence behavior in this sample an assumption of the existence of trapping centers that has quantum dot-like effect is introduced. These trapping centers are due to In-atom segregation during growth, a multi-peak Gaussian fitting showed additional broad peak in the high energy side of the photoluminescence spectrum which is attributed to the segregated In-atoms. The segregated In-atoms cause additional confinement to be added to the system, and hence excitons survive longer with temperature. The results show that electron hole pairs in the studied quantum well sample are weakly correlated in the near room temperature region.