Free electron distribution in δ-doped InGaAs/AlGaAs pseudomorphic high electron mobility transistor structures

The free electron distribution in δ-doped high electron mobility transistors with pseudomorphic InGaAs wells is calculated self-consistently. The electron distribution is calculated from the single-particle wave functions obtained from a four-band k⋅p theory. The Hartree part of the Coulomb interaction is obtained from the Poisson equation and the exchange-correlation part from density functional theory within the local-density approximation. The calculated energy separations between the electron and hole subbands agree well with observed peak positions in photoluminescence data. In addition, it is found that for spacer layers thicker than about 40 Å and a δ-doping density of about 5×1012 cm−2, the δ layer can form a channel as deep as the p well and can draw electrons from the latter.