Electric Field In Depletion Region Research Articles

Leakage current transport mechanism under reverse bias in Au/Ni/GaN Schottky barrier diode

The leakage current transport mechanism under reverse bias of Au/Ni/GaN Schottky diode is studied using temperature dependent current-voltage (I-V-T) and capacitance-voltage (C-V) characteristics. I-V measurement in this study is in the range of 140 K–420 K in steps of 10 K. A reduction in voltage dependent barrier height and a strong internal electric field in depletion region under reverse bias suggested electric field enhanced thermionic emission in carrier transport via defect states in Au/Ni/GaN SBD. A detailed analysis of reverse leakage current revealed two different predominant transport mechanisms namely variable-range hopping (VRH) and Poole-Frenkel (PF) emission conduction at low (<260 K) and high (>260 K) temperatures respectively. The estimated thermal activation energies (0.20–0.39 eV) from Arrhenius plot indicates a trap assisted tunneling of thermally activated electrons from a deep trap state into a continuum of states associated with each conductive threading dislocation.

Strong correlation between capacitance and breakdown voltage of GaInN/GaN light-emitting diodes

Investigating the relationship between the breakdown voltage and the capacitance of GaInN light-emitting diodes (LEDs), we find that a lower capacitance due to weaker internal electric field in depletion region or wider depletion width at the pn junction results in lower reverse leakage current and thus larger breakdown voltage. The measured breakdown voltage and capacitance of LEDs show a strong correlation, opening a nondestructive and non-intrusive way to estimate the breakdown voltage of an LED based on the capacitance-voltage measurement.