Extremely low inhomogeneous broadening of exciton lines in shallow (In,Ga)As/GaAs quantum wells

• Published in: Solid state communications Vol. 199; pp. 47 - 51
• Main Authors: Poltavtsev, S.V., Efimov, Yu.P., Dolgikh, Yu.K., Eliseev, S.A., Petrov, V.V., Ovsyankin, V.V.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.12.2014
• Subjects: A. MQW Bragg structures; A. Single (In, Ga)As QW; D. Inhomogeneous broadening; E. Brewster angle; E. Brewster angle; A. MQW Bragg structures; D. Inhomogeneous broadening; A. Single (In, Ga)As QW
• ISSN: 0038-1098; 1879-2766
• DOI: 10.1016/j.ssc.2014.09.005

We study radiative linewidth of exciton resonance in shallow InxGa1−xAs/GaAs single quantum wells as a function of indium concentration in the range x=0.02…0.10 and well thickness in the range LZ=1…30nm using method of Brewster reflection spectroscopy. Record linewidths of heavy-hole exciton resonance of about 130…180μeV are measured in reflection spectra for single quantum wells with LZ=2nm and x=0.02 at temperature of 9K. In these spectra, the non-radiative linewidth including inhomogeneous broadening can be comparable or even less than radiative linewidth. It is shown that radiative linewidth weakly depends on x and LZ in these ranges. In multiple-quantum-well Bragg structure with ten periods, the oscillator strength per individual quantum well is similar to that of single quantum well, while the total radiative linewidth exceeds inhomogeneous broadening by 4 times.