A detailed study on current-voltage characteristics of Au/n-GaAs in wide temperature range

In order to obtain the detailed information on the conduction mechanisms of the Au/n-GaAs Schottky barrier diode (SBD), the current-voltage (I-V) characteristics were carried out in the temperature range of 80-340 K by the steps of 20 K. The ideality factor (n) decreases, while the effective barrier height (Phi(Bo)) increases with increasing temperature (80-340 K). The semilogarithmic I-V curve is almost parallel for each temperature. Therefore, its slope and tunneling parameter (E-oo) remained almost constant as independent of temperature with an average of 27.47 V-1 and 28.04 meV, respectively. Furthermore, the reverse saturation current (I-s) ranges, indication that the charge transport mechanism in the Au/n-GaAs SBD is tunneling due to the weak temperature dependence of the I-s. Thus, it can be said that the experimental I-V data quite well obey the thermionic field emission (TFE) model especially at low temperatures rather than the other transport mechanisms. On the other hand, an abnormal decrease in the Phi(Bo) and increase in the n with decreasing temperature have been observed which leads to non-linearity in the activation energy plots and a linear relationship between the barrier heights (BHs) and the ideality factors of the SBD. The high value of n especially at low temperatures cannot be also explained only TFE theory. Therefore, we tried to explain the non-ideal behavior of the forward-bias I-V characteristics in Au/n-GaAs SBD with the basis of a thermionic emission (TE) mechanism with a Gaussian distribution (GD) of the BHs. The obtained results show that the temperature dependence of forward bias I-V characteristics of the Au/n-GaAs SBD can be successfully explained in terms of the TE mechanism with a double GD of BHs for low bias region (LBR) and moderate bias region (MBR). (C) 2013 Elsevier B.V. All rights reserved.