Analytical modelling of carrier transport mechanisms in long wavelength planar n+–p HgCdTe photovoltaic detectors

• Analytical modelling of electrical characteristics of LWIR HgCdTe photodiodes.
• Effect of surface treatment on the leakage current of the diodes investigated.
• Excess dark current shown to be closely associated with the diode’s shunt resistance.
• Quadratic dependence of the excess dark current on the applied reverse bias voltage.

The dark electrical characteristic of n+ on p long wavelength Hg1−xCdxTe photovoltaic detectors has been studied as a function of applied bias voltages. The diodes under study were given different surface treatments prior to their passivation. The dark current components have been identified using the already known carrier transport mechanisms across the junction. It is reported that the diodes under investigation have an excess leakage current component that exhibits quadratic dependence on the applied reverse bias voltage across the diode. The origin of this excess current is found to be closely associated with the ohmic currents. The diodes with higher ohmic current exhibit higher excess leakage current.