TRAPPING AND RELAXATION OF CHARGE AT STRUCTURAL DEFECTS IN EPITAXIAL GALLIUM-ARSENIDE

Deep trapping levels with activation energies of 0.54 eV and 0.48 eV a re detected in n-GaAs/i-GaAs epitaxial structures by the transient tra nsverse acoustoelectric voltage (TAV) and transient interface capacita nce methods. The transient TAV method is used to determine the relaxat ion times and effective capture cross sections of electrons at these c enters. Two techniques are compared: continuous-wave and pulsed measur ement of the transverse acoustoelectric voltage. Both techniques give identical values of the relaxation times within the measurement error limits. Continuous-wave measurements are more practical for the determ ination of short relaxation times (<1 ms), and the pulsed technique is preferable for the determination of longer relaxation times (>1 ms). (C) 1996 American Institute of Physics.