Piezophototronic effect enhanced luminescence of zinc oxide nanowires

Highlights: • Quantum mechanics analysis of the stimulated emission of ZnO nanowires is conducted. • Mechanically induced piezoelectric charges enhance the stimulated emission intensity. • Bandgap depending on the nanowire diameter determines the emitted optical spectrum. Experimental findings on electroluminescence or photoluminescence of ZnO nanowires have been drawn much attention due to their promising applications in many areas. One of the current challenges on this technology is a deeper understanding of this phenomenon in order to adopt it into practical device designs. In this work, a theoretical analysis of the stimulated emission of ZnO nanowires taking into consideration of the piezotronics effect has been conducted using the quantum mechanics theory. It is revealed that extra piezoelectric charges induced by applied mechanical forces increase the overall charge density of the nanowire, subsequently enhancing the emission intensity. Electronic bandgap varying with the diameter of the nanowire determines the peak value in the electromagnetic spectrum. Both wavelength and intensity of the stimulated emission can be tuned by controlling the dimension of the nanowires and external applied mechanical forces.