Analysis of electronic parameters and frequency-dependent properties of Au/NiO/n-GaN heterojunctions

Abstract

The electrical and frequency-dependent properties of ten Au/NiO/n-GaN heterojunctions fabricated with similar conditions are assessed by I–V, C–V, and G–V measurement methods. In addition, C–f and G–f measurements are conducted in the frequency range of 1 kHz–1 MHz. The electronic parameters are changed from junction to junction even if they are fabricated in the similar way. The calculated barrier height and ideality factor values are fitted by the Gaussian distribution function. Statistical analysis of the data provides the mean barrier height and ideality factor values of 0.84 eV and 2.70 for the heterojunction. Besides, the mean barrier height (Ф b), donor concentration (N d), space charge layer width (W D), and Fermi level (E F) are determined from the C–V data and the corresponding values are 1.30 eV, 2.00 × 1017 cm−3, 8.222 × 10−6 cm, and 0.018 eV, respectively. The interface state density (N SS) and relaxation time (τ) are assessed from C–f and G–f measurements. Moreover, the dielectric constant (e′), dielectric loss (e″), tangent loss (tan δ), and electrical conductivity (σ ac) are determined from C–f and G–f data in the frequency range of 1 kHz–1 MHz with various biases (0.1–0.6 V). e′ and e″ are decreased with increasing frequency.