Influence of temperature and illumination on the electrical properties of p-ZnTe/n-CdTe heterojunction grown by molecular beam epitaxy

Abstract

A set of p-ZnTe/n-CdTe heterojunctions were grown on conducting GaAs substrates by molecular beam epitaxy. The current density–voltage (J–V) and capacitance–voltage (C–V) characteristics measured in the temperature range 300–400 K were analysed in order to reveal the dominant carrier transport mechanisms through the junctions. The C–V measurements show that the device is linearly graded. The temperature dependence of the built-in potential and the impurity gradient of the device were determined. The deep defect states govern the current flow through the junctions. The measurements under the lower voltage region (V < 0.35 V) reveal at the p-ZnTe/n-CdTe interface, the presence of deep defect states with the activation energy of 0.52 eV. Under the higher forward bias voltage (V > 0.35 V), the space-charge-limited current governed the J–V characteristics with a single traps level, ΔE t = 0.55 eV. The p-ZnTe/n-CdTe device under different illumination intensities exhibit a significant photosensitivity proving that this kind of heterostructure can be regarded as a good candidate for photodiode applications.

Electrical Properties of p-ZnTe/n-CdTe Photodiodes

“…In addition, the theoretical limit for the solar energy conversion efciency is relatively high it exceeds 20%. Because of these reasons the p-ZnTe/n-CdTe heterojunctions are interesting candidates for solar applications [5,6].…”

Computation of Heterojunction Parameters at Low Temperatures in Heterojunctions Comprised of n-Type β-FeSi2 Thin Films and p-Type Si(111) Substrates Grown by Radio Frequency Magnetron Sputtering

“…If the value is greater than one and lower than or equal to two, the transportation mechanism across the junction of the carrier is dominated by a generationrecombination (G-R) process. Besides, the transportation mechanism of the carrier is probably governed by a carrier tunneling process if the value is greater than two [22]. Figure 4 illustrates a plot of value versus the temperature for the present heterojunctions.…”

“…The heterojunctions possess a large value for n, which is likely owing to the presence of a flawed contact behavior as well as the result of inhomogeneity and tunneling [25]. When the values of 0 become known, the value for activation energy ( ) can be computed by the following relation [21,22,26]: Figure 5 illustrates an Arrhenius plot for ln 0 versus 1000/T. From the plot, the 0 value was 5.34 × 10 −4 A/cm 2 at room temperature and decreased to 9.93 × 10 −12 A/cm 2 at 20 K. The two regions indicate that there are two values for in the present heterojunctions.…”

Fabrication and Photovoltaic Properties of Organic Solar Cell Based on Zinc Phthalocyanine

“…The slope greater than 2 in region II of Figure 5d demonstrates that the dominant transport mechanism in this region is trap-charge-limited current (TCLC) with exponential distribution of traps. In the presence of traps, the current density can be expressed as [50]:…”