Electron trap level in a GaN nanorod p-n junction grown by molecular-beam epitaxy

We have studied the electrical properties of a GaN nanorod p-n junction diode by deep level transient spectroscopy measurements. The p-n junction nanorods were patterned on a Si O2 substrate by using e-beam lithography. In order to confirm the formation of p-n junction, cathodoluminescence and current-voltage measurements, as a function of temperature, were made. The current-voltage curve exhibits strong temperature dependence, suggesting that thermionic emission over a barrier dominates. This barrier most likely corresponds to emission from a deep level in the band. The deep level appears to be an electron trap at Ec-0.40 eV below the conduction band with a capture cross section of 2.22×10 cm2 near the depletion region of the p-n junction.