Electrical characteristics of Schottky diodes based on semi-insulating CdTe single crystals

Abstract

Electrical properties of Schottky diodes fabricated by vacuum evaporation of Al on the surface of semi-insulating p-like CdTe single crystals have been investigated. The current-voltage characteristics (CVCs) of the diodes have an unconventional pattern which is manifested in the absence of rectification at both low forward bias voltages (<5V) and reverse bias in a wide range of voltages. The linear behavior of CVC is shown to be caused by a very high resistance of the CdTe substrate. In order to exclude an influence of the substrate and obtain the real CVC of the Al∕CdTe contacts, the samples were illuminated with low absorption light. A sharp increase in the forward current at higher voltages (>5V) is associated with the injection of minority carriers into the bulk of the crystals.

Higher voltage X- and γ-ray Schottky diode detectors with low leakage current

“…1 shows the low-voltage parts of the current-voltage (J-V) characteristics of one of the obtained detectors with Ni/CdTe/Ni electrode configuration plotted in linear coordinates of one of the obtained diode structures. As seen, pronounced rectifying properties of the diode are observed starting from the lowest voltages that distinguishes it from the diodes described in both [5], [6] and our previous paper [8].…”

“…In fact, at the lowest voltages rectifying is not observed and, to the contrary, the forward current steeply increases as far as V exceeds a few volts. The AI/CdTe Schottky contacts have also similar properties and can be explained by modulation of the conductivity of the bulk part of the CdTe crystal as a result of injection of minority carriers at higher forward voltage [12], while at low voltages, rectifying properties of a Schottky contact is masked by series high resistance of the CdTe crystal [8].…”

“…The most widely used CdTe diode detectors are constructed as a combination of a Schottky barrier and ohmic contact on the opposite surfaces of the crystal and they exhibit much lower leakage current than detectors with two ohmic contacts. Two different metals and two technology procedures are commonly used to form Schottky and ohmic contacts, respectively [1 ]- [8], [11], [12]. The In/CdTe/Pt Schottky diode X-and y-ray detectors differ from those with ohmic contacts in that for an increase in the charge collection efficiency and the width of the active region, they allow to raise the applied voltage at low dark currents [5], [6].…”

Modelling of degradation/recovery phenomena in CdS/CdTe ultrathin film solar cells

“…We note here that our approach is not modelling the inter-diffusion of the Cu ions through grain boundaries, but we assume that the grains size (C1 lm) is as big as the CdTe layer and the defective particles are diffusing though bulk CdTe. This approach can be extended to the other type of materials such as radiation detectors based on CdTe and CdZnTe as well as thin-film solar cells based on CIGS and CZTS materials [6][7][8]. Further investigations are required for the realization of durable and stable semi-transparent PV windows using ultrathin films proposed and practically introduced by Plotnikov et al [9].…”

Studies on morphological change and optical properties for various Zn concentrations in CdTe thin film prepared by stacked elemental layer method

“…To achieve perfect ternary CdTe-based compounds such as CZT, it is essential to understand the atomic and electronic structure and the incorporation kinetics of Zn doping in CdTe [15][16][17] and the contact performance depends strongly both on the electrode metal and semiconductor surface preparation before metallization [18]. This led to an increasing interest in the development of wide band gap absorbers based on the alloys of ZnTe and CdTe, with a variety of advantageous properties.…”