Dynamical model for piezotronic and piezo-phototronic devices under low and high frequency external compressive stresses

Abstract

Dynamical theories for piezotronic and piezo-phototropic devices are incomplete. In this work, we aim to establish a theoretical method for modelling dynamic characteristics of devices exhibiting these two emerging phenomena. By taking the simplest piezotronic device-PN junction as an example, we develop a small signal model and the united approach to analyze its diffusion capacitance and conductance under both low and high frequency external compressive stresses, which is different from the traditional considerations that treat the piezopotential as a static value. Furthermore, we expand the theory into piezo-phototronic devices e.g., a light emitting diode (LED). The dynamic recombination rate and light emitting intensity are quantitatively calculated under different frequencies of external compressive stresses. The work complements existing works that only consider the static cases. The work can shed light in future high frequency piezoelectronic devices exploration.