Giant piezoelectric resistance effect of nanoscale zinc oxide tunnel junctions: first principles simulations

Based on first principles simulations and quantum transport calculations, we have investigated in the present work the effect of the mechanical load on transport characteristics and the relative physical properties of nanoscale zinc oxide (ZnO) tunnel junctions, and verified an intrinsic giant piezoelectric resistance (GPR) effect. Our results show that the transport-relevant properties, e.g., the piezoelectric potential (piezopotential), built-in electric field, conduction band offset and electron transmission probability of the junction etc., can obviously be tuned by the applied strain. Accordingly, it is inspiring to find that the current-voltage characteristics and tunneling electro-resistance of the ZnO tunnel junction can significantly be adjusted with the strain. When the applied strain switches from -5% to 5%, an increase of more than 14 times in the tunneling current at a bias voltage of 1.1 V can be obtained. Meanwhile, an increase of up to 2000% of the electro-resistance ratio with respect to the zero strain state can be reached at the same bias voltage and with a 5% compression. According to our investigations, the giant piezoelectric resistance effect of nanoscale ZnO tunnel junctions exhibits great potential in exploiting tunable electronic devices. Furthermore, the methodology of strain engineering revealed in this work may shed light on the mechanical manipulations of electronic devices.