Electrical characterization of strained InP-Ga(x)In(1-x)As core-shell nanowires

Abstract: This project report attempts to measure the piezoelectric effect in strained core-shell nanowires. The core material is wurtzite indium phosphide (InP) and the shell material wurtzite gallium indium arsenide (Ga(x)In(1-x)As). The lattice constant of Ga(x)In(1-x)As can be adjusted by its composition x and enables positive and negative strain for core and shell. A piezoelectric field in the order of volt per micrometer was predicted using analytical calculations of the strain. The nanowire samples are grown using metal-organic vapor phase epitaxy (MOVPE), resulting in nanowires with varying shell thickness and shell composition. Single nanowires were contacted to measure their current voltage characteristics. The extracted resistance and rectication behavior was dominated by the shell thickness for the case of thin shells (<10 nanometer). The characteristics of a piezoelectric field, however, could not be extracted from the measurement results.