Barrier characteristics of Cd/p-GaTe Schottky diodes based onI V Tmeasurements

Abstract

The current-voltage (I-V ) characteristics of Cd/p-GaTe Schottky barrier diodes were measured in the temperature range 90-330 K. The apparent barrier height and the ideality factor derived by using thermionic emission (TE) theory were found to be strongly temperature dependent. Evaluating forward I-V data reveals a decrease of zero-bias barrier height ( b0 ) but an increase of ideality factor (n) with decrease in temperature, and these changes are more pronounced below 150 K. The conventional Richardson plot exhibits nonlinearity below 150 K with the linear portion corresponding to an activation energy of 0.52 eV. The value of effective Richardson constant (A * ) turns out to be 6.74 × 10 −2 A K −2 cm −2 against the theoretical value of 119.4 A K −2 cm −2 . It is demonstrated that the findings cannot be explained on the basis of tunnelling and image force lowering effects. Also, the concept of the flat-band barrier height f b fails to account for the temperature dependence of the diode parameters. Finally, it is demonstrated that these anomalies result due to the barrier height inhomogeneities prevailing at the metal-semiconductor interface. The inhomogeneities are considered to have Gaussian distribution with a mean barrier height of ¯ b0 = 0.886 eV and a standard deviation of σ s0 = 0.091 eV at zero bias. Furthermore, the mean barrier height and the Richardson constant values were obtained as 0.875 eV and 62.2 A K −2 cm −2 , respectively, by means of the modified Richardson plot, ln(J 0 /T 2 ) − q 2 σ 2 s0 /2k 2 T 2 versus 1000/T. Hence, it has been concluded that the temperature dependence of the I -V characteristics of the Schottky barrier on p-type GaTe can be successfully explained on the basis of TE mechanism with Gaussian distribution of the barrier heights.

Measurement and modelling of the characteristic parameters for silver Schottky contacts on layered p-GaSe compound in a wide temperature range

“…In contrast to other layered semiconductors [17][18][19][20][21], to my knowledge, measurements and modelling of the characteristic parameters for silver SBDs fabricated on p-GaSe have not yet 0925-8388/$ -see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.jallcom.2010.07.034 been reported.…”

Structural and electrical characterization of ZnO-based homojunctions

“…The Richardson constant is usually determined from the intercept of ln(J 0 /T 2 ) vs. 1000/T graph [33,38,39]. The experimental data are shown to fit asymptotically with a straight line at higher temperatures only, yielding a Richardson constant (A*) of 0.062 A cm −2 K −2 , which is much lower than the known theoretical value of 32 A cm −2 K −2 for ZnO (Fig.…”

“…In other words, the current of the diode will flow preferentially through the lower barriers in the potential distribution. A* value obtained from the temperature dependence of the I-V characteristics may be affected by the lateral inhomogeneity of the barrier, and the fact that the different value from the theoretical one may be connected to a value of the real effective mass that is different from the calculated one [33,38,39,[43][44][45][46][47][48][49].…”

“…Generally, it is known that the ideality factor n increases while the zero bias barrier height˚b 0 decreases with decreasing temperature [33]. The experimental ideality factor (n) (denoted by closed circles), and the apparent ideality factor (n ap ) (denoted by open squares) are shown in Fig.…”

“…Sometimes, the interface barrier inhomogeneity is responsible for the apparent increase in the barrier height. In fact, the I-V characteristics do not necessarily represent the true mean barrier height at a particular temperature [33,37].…”