Determination of low temperature impact ionization coefficients in GaAs by electroluminescence measurements on single barrier tunneling structures

Abstract
Measurements of the absolute intensity of electroluminescence (EL) due to impact ionization in n-type GaAs/AlGaAs single barrier tunneling structures are reported. These measurements yield values for the impact ionization coefficient (α) for electrons in GaAs as a function of electric field at a temperature of 5 K. Structures with undoped high field regions of length 100, 150, and 200 nm are shown to give very similar quantitative results for α. Very good agreement is obtained with the results of low temperature carrier multiplication measurements, carried out independently on a bulk GaAs p-i-n diode, thus establishing EL studies as a reliable quantitative probe of impact ionization phenomena.