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1991
Journal Article
Titel
Electrical, magnetic circular dichroism and Raman spectroscopic investigations on the EK2 double acceptor -78/203 meV- in GaAs.
Alternative
Elektrische, MCD und Ramanspektroskopische Untersuchung des EK2 Doppelakzeptors -78/203 meV- in GaAs
Abstract
The electrical and optical properties of liquid encapsulated Czochralski grown, Ga-rich (melt composed of 55% Ga and 45% As), p-type GaAs were studied by the Hall effect, capacitance-voltage measurements, magnetic circular dichroism, optically detected electron spin resonance, deep level transient spectroscopy (DLTS), and Raman spectroscopy. Two levels with inonization energies of 78 and 203 meV above the valence band edge were examined and fitted to the singly and doubly charged ground states of a double acceptor which is designated an EK2 center. The Raman scattering cross sections for electronic excitations were determined from the defect concentrations measured by DLTS. The EK2 center is electrically passivated via a remote microwave hydrogen plasma technique. It can be reactivated by heat treatments with an activation energy of E sub a = 1.4 eV. The concentrations of the two levels were equal to each other in four as-grown samples, in samples following passivation, and at all stag es during the subsequent reactivation. The observations are inconsistent with previous suggestions that the levels are due to two separate defects.