A Systematic Study of Composition-Dependent Band Offsets at Strained (In)GaAs(N)/GaAs Heterointerfaces for Optoelectronic Applications

Abstract

The values of band offsets in lattice-matched and pseudomorphically strained In_xGa_1–xAs_1–yN_y/GaAs (001) heterointerfaces, with different indium \(\left( {0 \leqslant x \leqslant 1} \right)\) and low nitrogen compositions \(~\left( {0 \leqslant y \leqslant 0.05} \right)\), have been calculated on the basis of the Model Solid Theory. Our obtained results reveal that conduction and valence band states are significantly influenced as indium composition is changed, while nitrogen incorporation affects more the conduction band than the valence band. In fact, with increasing N composition, a dramatic conduction band energy change is reported, while the valence band offset varies weakly, about 20 meV per nitrogen concentration in %. Additionally, our results suggest a type II band lineup for both GaAs_1‒yN_y/GaAs and lattice matched In_xGa_1–xAs_1–yN_y/GaAs heterojunctions. The type I alignment in strained In_xGa_1–xAs_1–yN_y/GaAs is found to be achieved at relatively high In molar fraction and very low nitrogen compositions. Detailed information and results derived from this study will contribute in designing novel systems in a spectral range of high importance for optoelectronic devices including photodetectors, light emitters and more especially multijunction solar cells.