Improved photoresponse of a-axis GaN microwire/p-polymer hybrid photosensor by the piezo-phototronic effect

Abstract

The piezo-phototronic effect, as an effective interfacial regulating strategy, utilizes piezoelectric polarization charges present at the local junction/interface to modulate the optoelectronic processes of charge carrier such as generation, separation, transport and recombination, which is in close relationship with crystal orientation of the piezoelectric semiconductors. In this work, the piezo-phototronic effect is utilized to modulate the photoresponse performances of a-axis GaN microwire/p-polymer inorganic/organic hybrid photosensor. The output photocurrent experiences an increase followed by a decrease as increasing compressive strain, while it decreases monotonously as increasing tensile strain, resulting in a maximum values at each light intensity under a certain compressive strain. Besides, the modulation of photoresponse by the piezo-phototronic effect is more significant under weak illumination condition. By applying a −0.32% compressive strain, the sensitivity and responsivity of the hybrid photosensor are greatly enhanced by 508% and 354%, respectively. Two independent processes that affect photogenerated charge carriers separation and transport by strain are discovered, which is different from those normally investigated in c-axis hybrid nanostructures.