Influence of a Strong Electric Field on the Carrier Capture by Nonradiative Deep‐Level Centers in GaAs

The techniques of capacitance spectroscopy are used to measure directly electron and hole capture cross‐sections of deep levels in a neutral material at zero electric field and in the depletion layer with a strong electric field. The data show that if at zero electric field the electron capture cross‐sections onto the centers are thermally activated and described by the theory of nonradiative multiphonon capture, then in a strong electric field (F ≈ 104 V/cm) the capture cross‐sections increase to the limiting large value (σ ≈ 10−14 to 10−12 cm2) and are only little dependent on temperature. It is shown that an electric field causes a simultaneous increase of the electron and hole capture cross‐sections of the level EL2 by five orders of magnitude at low temperatures (T ≈ 90 K).