Built-in biaxial strain dependence of Γ-X transport in GaAs/InxAl1−xAs/GaAs pseudomorphic heterojunction barriers (x=0, 0.03, and 0.06)

The effects of built‐in biaxial strain on Γ‐X transport in n‐GaAs/i‐InxAl1−xAs/n‐GaAs pseudomorphic single‐barrier structures (x=0, 0.03, and 0.06) are studied by measuring temperature‐dependent I‐V characteristics. For the accurate characterization of electron transport across each barrier, a self‐consistent numerical model is used to analyze the experimental results. For each structure, the four barrier parameters defined from the thermionic‐field‐emission theory, the effective Richardson constant A∗, the conduction‐band offsets ΔEc1,2, and a tunneling mass mn∗ are extracted by calculating the theoretical I‐V characteristics and fitting them to the experimental I‐V‐T data. The experimentally obtained X‐point conduction‐band shifts with the addition of indium are compared with the theoretical results calculated based on the model‐solid theory. The results indicate that the addition of indium not only splits the degenerate X minima of the InxAl1−xAs barrier, but also shifts the relative barrier heights of both longitudinal and transverse X valleys due to the alloy‐dependent band‐structure modification. The comparison between the experimental and theoretical results illustrates that the transverse X valleys are the main conduction channel for the Γ‐X transport across InxAl1−xAs pseudomorphic barriers. © 1994 American Institute of Physics