Valence-band offsets in strained SiGeSn/Si layers with different tin contents

Admittance spectroscopy is used to study hole states in Si 0.7– y Ge 0.3 Sn y /Si quantum wells in the tin content range y = 0.04–0.1. It is found that the hole binding energy increases with tin content. The hole size-quantization energies in structures containing a pseudomorphic Si 0.7– y Ge 0.3 Sn y layer in the Si matrix are determined using the 6-band kp method. The valence-band offset at the Si 0.7– y Ge 0.3 Sn y heterointerface is determined by combining the numerical calculation results and experimental data. It is found that the dependence of the experimental values of the valence-band offsets between pseudomorphic Si 0.7– y Ge 0.3 Sn y layers and Si on the tin content is described by the expression Δ E V exp = (0.21 ± 0.01) + (3.35 ± 7.8 × 10 –4 ) y eV.