Study for Enhancement of Terahertz Radiation Using GaSb/InAs Heterostructures

Abstract

GaSb/InAs heterostructures were investigated for the enhancement of terahertz (THz) radiation from an InAs thin film excited by a femtosecond laser. Taking advantage of the large conduction band discontinuity between GaSb and InAs, electrons excited in the GaSb layer gain a large excess energy when injected into the InAs radiation layer. Enhancement of the THz radiation by a factor of approximately two was observed when the surface pinning position was controlled to reduce the surface electric field by the introduction of a thin InAs cap layer.