Enhancing the NIR Photocurrent in Single GaAs Nanowires with Radial p-i-n Junctions by Uniaxial Strain

III-V compound nanowires have electrical and optical properties suitable for a wide range of applications, including photovoltaics and photodetectors. Furthermore, their elastic nature allows the use of strain engineering to enhance their performance. Here we have investigated the effect of mechanical strain on the photocurrent and the electrical properties of single GaAs nanowires with radial p-i-n junctions, using a nanoprobing setup. A uniaxial tensile strain of 3% resulted in an increase in photocurrent by more than a factor of 4 during NIR illumination. This effect is attributed to a decrease of 0.2 eV in nanowire bandgap energy, revealed by analysis of the current-voltage characteristics as a function of strain. This analysis also shows how other properties are affected by the strain, including the nanowire resistance. Furthermore, electron-beam-induced current maps show that the charge collection efficiency within the nanowire is unaffected by strain measured up to 0.9%.

Automated summary

In this study, the effect of mechanical strain on the photocurrent and electrical properties of single GaAs nanowires with radial p-i-n junctions was investigated using a nanoprobing setup. A uniaxial tensile strain of 3% led to a significant increase in photocurrent during NIR illumination, attributed to a decrease in nanowire bandgap energy. Analysis also showed how other properties, including nanowire resistance, were affected by the strain. Additionally, electron-beam-induced current maps indicated that the charge collection efficiency within the nanowire was not affected by strain up to 0.9%.