Electrical transport and current properties of rare-earth dysprosium Schottky electrode on p-type GaN at various annealing temperatures

The electrical and current transport properties of rapidly annealed Dy/p-GaN SBD are probed by I-V and C-V techniques.The estimated barrier heights (BH) of as-deposited and 200 ℃ annealed SBDs are 0.80 eV (I-V)/0.93 eV (C-V) and 0.87 eV (I-V)/1.03 eV (C-V).However,the BH rises to 0.99 eV (I-V)/ 1.18 eV(C-V) and then slightly deceases to 0.92 eV (I-V)/1.03 eV (C-V) after annealing at 300 ℃ and 400 ℃.The utmost BH is attained after annealing at 300 ℃ and thus the optimum annealing for SBD is 300 ℃.By applying Cheung's functions,the series resistance of the SBD is estimated.The BHs estimated by I-V,Cheung's and ψs-Vplot are closely matched;hence the techniques used here are consistency and validity.The interface state density of the as-deposited and annealed contacts are calculated and we found that the Nss decreases up to 300 ℃ annealing and then slightly increases after annealing at 400 ℃.Analysis indicates that ohmic and space charge limited conduction mechanisms are found at low and higher voltages in forward-bias irrespective of annealing temperatures.Our experimental results demonstrate that the Poole-Frenkel emission is leading under the reverse bias of Dy/p-GaN SBD at all annealing temperatures.