Temperature dependence characteristics of dark current for arsenic doped LWIR HgCdTe detectors

Resistance–voltage (R–V) curves of arsenic doped long-wavelength infrared (LWIR) Mercury Cadmium Telluride (HgCdTe) photodiodes were measured in the temperature range of 59–92 K. The dark current characteristics of HgCdTe junction diode are presented by using a simultaneous-mode nonlinear fitting method. The observed R–V characteristics have been shown in agreement with the theoretical calculation by taking into account the contributions: (i) diffusion mechanism (Rdiff), (ii) generation–recombination mechanism (Rgr) in the depletion region, (iii) trap-assisted tunneling mechanism (Rtat), and (iv) band-to-band tunneling mechanism (Rbbt). Six characteristic parameters as function of temperature are extracted from the measured current–voltage (I–V) curves by considering the dominant current mechanisms under different bias levels. The fitted current components under different temperatures show that, as the temperature rises, the contribution to the dominant dark current component around maximum dynamic resistance range is changed from the trap-assisted tunneling and diffusion currents to the generation recombination effect. This change indicates that the dark current component may mainly be caused by the generation recombination current, which limits the performance of arsenic doped LWIR HgCdTe detectors.