Role of 0.66 eV dominant trap in annealed low-temperature grown molecular beam epitaxial GaAs

Abstract

The sample considered herein is an annealed low-temperature (LT) molecular beam epitaxially grown GaAs of n-LT-i-p structure with the LT layer grown at 300 degrees C. Characteristics involving the dominant trap level located at about 0.66 eV below the conduction band are obtained by analyzing the data of the admittance spectroscopy, capacitance-voltage, current-voltage, and frequency-dependent conductance experiments. This trap pins the fermi level of the LT layer and makes the LT layer semi-insulating. In this structure, the level interacts with both the conduction band and the valence band with a hole emission time constant characterized by an activation energy of 0.77 eV and a cross section of 1.1 X 10(-13) cm(2). This level is also an effective generation-recombination center when the temperature exceeds 300 K. (C) 1998 American Institute of Physics. [S0021-8979(98)04303-5].