Effect of annealing on the compositional modulation of InAlAsSb

Authors

N. Baladés, Universidad de CádizFollow
D. L. Sales, Universidad de Cádiz
M. Herrera, Universidad de Cádiz
F. J. Delgado, Universidad de Cádiz
M. González, Sotera Defense Solutions
K. Clark, Intelligent Epitaxy Technology, Inc.
P. Pinsunkajana, Intelligent Epitaxy Technology, Inc.
N. Hoven, Rochester Institute of Technology
S. Hubbard, Rochester Institute of Technology
S. Tomasulo, U.S Naval Research Laboratory
J. R. Walters, U.S Naval Research Laboratory
S. I. Molina, Universidad de Cádiz

Date of this Version

2017

Citation

Applied Surface Science 395 (2017), pp. 105–109.

Comments

U.S. government work.

Abstract

The effect of a post-growth thermal treatment in two different heterostructures with InAlAsSb as the top layer grown by molecular beam epitaxy lattice-matched to InP, have been studied by diffraction contrast transmission electron microscopy (TEM).¹ This novel top cell layer material with application in ultra-high efficiency solar cells were grown on (001) InP substrate with or without an InGaAs buffer layer. Initial photoluminescence (PL)² measurements revealed deviations from their predicted bandgap, suggesting non-random atomic distribution of the quaternary layer. Then, a thermal annealing was performed at different temperatures and times. The effect on the structure of the InAlAsSb active layer caused by the new arrangement of layers and the post-growth annealing treatments has been reported. Our results show that the small compositional fluctuations of the as-grown heterostructures disappear after being annealed, and the bandgap energy correspondingly increases towards the predicted value.