Role of contacts in characterization of deep traps in semi-insulating GaAsby thermally stimulated current spectroscopy

The role of contacts in characterization of traps in semi-insulating (SI) G aAs by thermally stimulated current (TSC) methods has been demonstrated by comparing alloyed In and soldered In contacts. Alloyed In contacts, which h ave an ohmic characteristic, assure high sensitivities in both TSC and temp erature dependent photocurrent (PC), and both are important for determining the trap concentrations in SI GaAs. On the other hand, soldered In contact s, which act like Schottky barriers, cause a significant reduction of both PC and TSC, particularly at low temperatures, and can lead to a misinterpre tation of TSC results.