NUMERICAL STUDY OF p-n INTERFACE EFFECTS TO ENHANCE PERFORMANCE OF PIEZOELECTRIC CORE-SHELL NANO WIRES

Abstract

simulated piezoelectric enhancements of p - n core shell nanowires with an inner-core cylinder of n-type ZnO and an outer-shell cylinder of p-type poly-3-hexylthiophene. Compared with conventional n-type ZnO nanowires, the piezoelectric potential of p - n core shell nanowires with the same dimensions (core part; n-ZnO), calculated by subtracting the electrical potential of the uncompressed core shell nanowires [phi(ele)(T-z = 0)] from that of compressed nanowires (phi(tota)(ele)l) according to phi(p-n)(piezo) phi(ele)(total)(T-z=0), are enhanced by more than a factor of 10. As the magnitude of vertical external compression (T-z) is varied from 0 to 9 x 10(7) N/m(2), the piezoelectric potential of the model system increases. This improvement in the piezoelectric potential is attributed to the presence of a depletion zone at the p - n interface (space-charge region), which reduces the carrier screening of the piezoelectric potential by removing free carriers. Our results suggest that the structure proposed here for p - n core shell rianowires could improve the performance of photovoltaic systems.