Impurity cluster effects in high- and low-doping semiconductor materials

摘要

The cluster-like impurity effect in semiconductor materials as Si, GaN, GaAs, and 4H-SiC for impurity concentrations spanning the metallic to the insulating regimes, i.e., from high- to low-doping concentration, has been investigated at low temperature. To metallic regime a critical impurity concentration for metal-nonmetal transition is estimated from a highly correlated system by a doubly doped H+2-like different impurity pairs. For insulating regime, the absorption measurements reveal low-energy absorption peaks identified as electronic transitions in three-donor clusters. The many-particle correlation via a multi-configurational self-consistent field model is used in the calculation.