Measurements of the band gap of wurtzite InAs1-xPx nanowires using photocurrent spectroscopy

We report measurements of the band gap of InAs1-xPx nanowires having wurtzite crystal structure as a function of the composition for 0.14 < x < 0.48. The band gap is measured by photocurrent spectroscopy on single InAs nanowires with a centrally placed InAs1-xPx segment. The photocurrent measurements are performed at a temperature of 5 K. The data fit well with a quadratic dependence of the band gap on the composition. Using a bowing parameter of 0.2 eV the extracted values for the band gaps are 0.54 eV for InAs and 1.65 eV for InP. These values are larger than the corresponding zinc blende band gaps. We attribute this increase to the fact that the crystal structure is wurtzite rather than zinc blende. (c) 2007 American Institute of Physics.