Bilateral piezoelectric charge modulation as a perspective of piezo-phototronic effect in tri-/multi-layer structured optoelectronics

Abstract

Mechanical stimulus produced piezoelectric charges could modulate the local energy band near interface to control the performances of electronics and optoelectronics, whereas almost half of the piezoelectric charges are electrostatically screened by the Ohmic contact and not effectively utilized. Multi-layer structured devices should be adopted to introduce multiple interfaces, so that most or even all of the piezoelectric charges could be effectively utilized. Such piezoelectric charge modulation on the multi-layer structured devices is proposed as Bilateral Piezoelectric Charge Modulation (BPCM). In this work, the concept of BPCM is illustrated and explained in detail and we further demonstrate the BPCM on the performances of a floating-base PNP heterojunction bipolar phototransistor (HBPT). The results indicate an interesting optimization modulation behavior. The working mechanism of BPCM in PNP HBPT is carefully illustrated and thoroughly discussed by analyzing the piezoelectric charges induced modulation of energy band near the two interfaces of PNP HBPT and its effects on photo-carriers’ dynamics. This work not only proposes the BPCM and further demonstrates it in a floating-base PNP HBPT successfully, but also presents the BPCM’s huge potential in advanced electronics and optoelectronics as a perspective of piezo-phototronic effect in multi-layer structured piezoelectric semiconductor devices.