Layer Perfection in Ultrathin, MOVPE-Grown InAs Layers Buried in GaAs(001) Studied by X-Ray Standing Wave and Photoluminescence Spectroscopy
J A. Gupta, Joseph Woicik, S P. Watkins, D A. Harrison, E D. Crozier, B A. Karlin
Using the In-L fluorescence produced by normal-incidence X-ray standing waves, we have measured the layer perfection and positions for ML = 1 and 1/2 (where ML = # of mono layers) InAs quantum wells buried in GaAs(001). Growth temperature effects were studied in a series of samples produced by metalorganic vapor phase epitaxy (MOVPE) at temperatures between 400 C and 600 C. The coherent position of the In atoms decreases with temperature in the ML = 1 samples, and the optimal growth temperature is near 550 C, as evidenced by the coherent position of 1.15 0.02 and the relatively high coherent fraction of 0.72 0.08. These results are corroborated by 1.6 K photoluminescence (PL) measurements in which the most sharp and intense In-excitonic emission is obtained from a sample grown at 530 C. For the ML = 1/2 samples, growth temperatures of 400 C and 600 C produce similar standing wave results: coherent positions of 1.09 0.02 and 1.10 0.02, coherent fractions of 0.75 0.10 and 0.74 0.11, respectively. However, PL reveals the higher temperature sample to be of far superior quality, due to excessive carbon incorporation at 400 C.
, Woicik, J.
, Watkins, S.
, Harrison, D.
, Crozier, E.
and Karlin, B.
Layer Perfection in Ultrathin, MOVPE-Grown InAs Layers Buried in GaAs(001) Studied by X-Ray Standing Wave and Photoluminescence Spectroscopy, Journal of Synchrotron Radiation
(Accessed December 10, 2023)