ELECTRIC-FIELD ENHANCED EMISSION FROM 2 ALPHA-PARTICLE IRRADIATION-INDUCED TRAPS IN N-GAAS

The electric field dependence of the emission rates of two alpha-parti cle irradiation-induced electron traps in epitaxially grown n-GaAs, E alpha 3 and E alpha 4, was studied using deep level transient spectros copy (DLTS). We found the emission enhancement from E alpha 4 to be mu ch more pronounced than that from E alpha 3, emphasising the differenc e in their structure. Neither of the two defects shows an emission enh ancement characteristic of the Poole-Frenkel effect, commonly assumed to account for field dependent emission enhancement. The phonon-assist ed tunnelling model accurately describes the field dependent emission enhancement of both the E alpha 3 and the E alpha 4 defects.