Study of the Characteristics Current-Voltage and Capacity-Voltage of Hg/GaN/GaAs Structures

In this paper, we have studied Hg/GaN/GaAs Schottky diode. The thin GaN film is realized by nitridation of GaAs substrates. The current-voltage (I-V) and capacitance-voltage (C-V) of Hg/GaN/GaAs structures were investigated at room temperature. The electrical parameters such as saturation current I-s (10(-8) A), ideality factor n (1.65), barrier height Phi(bn) (0.68 eV) and series resistance R-s (2.2 k Omega) were evaluated from I-V experimental data. The high ideality factor can be explained by various currents transport mechanisms (the generation-recombination, tunneling and leak currents) caused by inhomogeneities and defects at metal-semiconductor interface. We have also calculated the barrier height from C-V experimental data. The determined value is higher (4.98 eV) compared with the value obtained from I-V (0.68 eV) characteristic. We suggest that this is due to the presence of an additional residual capacity. So after the removal of this capacity, we find the following electrical parameters: doping concentration (N-D = 4 x 10(16) cm(-3)), diffusion voltage (V-d = 0.817 V) and Schottky barrier height (Phi(bn) = 0.943 eV).