Application of extended Hckel theory to GaAs, GaP, GaAs: N, and GaP: N

Extended Hckel theory is applied to GaP, GaAs, and to the nitrogen isoelectronic trap in GaP and GaAs. The theory confirms the A1-symmetric nature of the N-trap electron state NX (the A line in GaP) and lends support to the expectation that even small inward relaxation of the neighboring Ga atoms significantly lowers the NX binding energy (2 eV/). When compared with the results of Hsu's phenomenological one-band model, the present calculations indicate that a quantitative theory of the N trap (and all deep traps) in GaAs1-xPx must accurately account for the electronic structure of both the valence and the conduction bands. © 1980 The American Physical Society.