Effect of Uniaxial Stress on the Binding to Isoelectronic Impurities in GaP

Abstract

An unexpected sensitivity of binding energy to externally applied stress, recently predicted theoretically, has been verified experimentally for the isoelectronic traps N and Bi in GaP. This is done by accurately measuring the shift in binding energy for these centers relative to the shift observed for the exciton bound to the neutral sulfur donor, whose pressure behavior is expected to follow that of the band gap. It is found that the binding decreases approximately four times faster for N than for Bi as a function of uniaxial stress.