Investigation of deep electronic centers in low-temperature grown GaAs using extremely thin layers

Abstract

We report on an approach to investigate the deep electronic defect centers in low-temperature grown GaAs (LT-GaAs). Using an extremely thin LT-GaAs layer (comparable with the penetration depth of an electric field in bulk material) incorporated in the i layer of a p-i-n diode, we are able to charge or to deplete the deep centers in the energy gap by applying a reverse bias. The corresponding space charge is monitored by the field changes across the LT-GaAs layer, both optically by Franz–Keldysh experiments and electrically by n-channel conductance changes. From our results, we derive a deep trap density of 1018 cm−3 centered at around 500–700 meV below the conduction band.