Radiative and Nonradiative Tunneling in Nanowire Light-Emitting Diodes

We investigated the temperature dependence of the I-V and emission properties of InP nanowire light-emitting diodes (LEDs) grown by selective-area metal-organic vapor-phase epitaxy in detail to elucidate their carrier injection and recombination mechanisms. Very weak temperature dependence of the I-V characteristics revealed that carrier transport occurred with tunneling through the pn junction. In addition, our observation in the bias-voltage dependence of electroluminescence (EL) peak position and intensity, and photon energy dependence of the low-energy tail of EL peaks at low temperature indicated the radiative tunneling. A discrepancy of the tunneling factor between I-V characteristics and EL was found, suggesting the existence of a large nonradiative component in the tunneling current.