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The current-voltage (I-V) and capacitance-voltage (C-V ) characteristics of Au/n-GaAs contacts have been measured in the temperature range of 80-300 K. An abnormal decrease in the experimental BH b and an increase in the ideality factor n with a decrease in temperature have been observed. This behaviour has been attributed to the barrier inhomogeneities by assuming a Gaussian distribution of barrier heights at the metal-semiconductor interface. The temperature-dependent I -V characteristics of the Au/n-GaAs contact have shown a double Gaussian distribution giving mean barrier heights of 0.967 and 0.710 eV and standard deviations of 0.105 and 0.071 V, respectively. A modified ln(I 0 /T 2 ) − q 2 σ 2 s 2k 2 T 2 versus 1/T plot for the two temperature regions then gives ¯ b0 and A * as 0.976 and 0.703 eV, and 13.376 and 8.110 A cm −2 K −2 , respectively. Furthermore, a value of −0.674 meV K −1 for the temperature coefficient has been obtained, and the value of −0.674 meV K −1 for the Au/n-GaAs Schottky diode is in close agreement with those in the literature.

The current-voltage (I-V) characteristics of Ni/4H-nSiC Schottky diodes have been measured in the temperature range of 180–300 K with a temperature step of 20 K. An experimental barrier height (BH) Φap value of about 1.32 eV was obtained for the Ni/4H-nSiC Schottky diode at the 300 K. A decrease in the experimental BH Φap and an increase in the ideality factor n with a decrease in temperature have been explained on the basis of a thermionic emission mechanism with Gaussian distribution of the barrier heights due to the BH inhomogeneities at the metal-semiconductor interface. Φ¯b and A* as 1.71 eV, and 156.3 A/cm2 K2, respectively, have been calculated from a modified ln(I0/T2)−q2σs2/2k2T2 vs 1/T plot using the temperature-dependent experimental I-V characteristics of the Ni/4H-nSiC contact. The Richardson constant value of 156.3 A/cm2 K2 is in close agreement with 146 A/cm2 K2 known for 4H-nSiC.

We report the current-voltage (I-V) and capacitance-voltage characteristics (C-V) of Ni/n-GaN Schottky diodes. Gallium nitride is a highly promising wide band gap semiconductor for applications in high power electronic and optoelectronic devices which require Schottky barriers for modulating the channel mobile charge. The I-V and C-V characteristics of the diodes have been measured in the temperature range of 80–400 K with steps of 20 K. Thermal carrier concentration and barrier height versus temperature plots have been obtained from the C−2-V characteristics, and a value of α=−1.40 meV/K for temperature coefficient of the barrier height. The modified activation energy plot according to the barrier inhomogeneity model has given the Richardson constant A∗ as 80 or 85 A/(cm2 K2).