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The temperature-dependent optical absorption of 3D arrays of close-packed strongly quantized ZnSe QDs, deposited in thin film form, is studied in the interval from 11 to 340 K. Because of the particle size distribution and interdot coupling between proximal QDs within the QD arrays, the excitonic peaks are not visible at all, even at temperatures as low as 11 K. The temperature coefficient of the band-gap energy in the strongly quantized QD arrays was found to be twice larger than the value characteristic of a bulk ZnSe specimen. The Debye temperature, on the other hand, is shown to decrease by about 15% in comparison with the bulk value, which is attributed to the phonon confinement effects. It is shown that the sub-band-gap exponential absorption tails in the strongly quantized 3D QD arrays obey the Urbach−Martienssen rule. The temperature dependence of the Urbach energy and the relation between this quantity and the band-gap energy of the films could be excellently fitted to the predictions of the Cody’s model. However, in contrast to the macrocrystalline semiconductors, the temperature-dependent component of the Urbach energy accounts for less than 15% of the overall value, which is attributed to the very high degree of inherent structural disorder in the QD arrays. This is in line with the conclusions derived from analyses of the temperature dependence of the steepness parameter, σ, which imply a rather high energy of the phonons contributing to the Urbach−Martienssen tails in the optical absorption of the QD arrays.

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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.

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