Field-enhanced emission rate and electronic properties of a defect introduced in n-GaN by 5.4 MeV He-ion irradiation

A deep level defect ER3, introduced in n-GaN by high energy (5.4 MeV) He ions, was characterized by deep level transient spectroscopy (DLTS). This defect, 0.196±0.004 eV below the conduction band, with an apparent capture cross-section of 3.5±1×10−15 cm2, is introduced uniformly in the region profiled by DLTS at a rate of 3270±200 cm−1. The emission rate of this defect depends on the electric field strength in the space-charge region. This emission rate is modeled according to the Poole–Frenkel distortion of a square well with a radius of 20±2 Å or alternatively, a Gaussian well with a characteristic width of 6.0±1 Å. Hence, we conclude that ER3 is a point defect which has a field dependence not explained by the classical Poole–Frenkel enhancement.