Comparative study on dark current mechanisms of n-on-p and p-on-n long-wavelength HgCdTe infrared detectors

•The J-V curves of long-wavelength MCT infrared detectors with planar n-on-p and p-on-n structures are measured and compared in the temperature range of 55–130 K.•The dark current of p-on-n device is around one order of magnitude lower than that of n-on-p device at small reverse bias voltage due to the suppression of diffusion current.•The TAT current is more obvious for n-on-p device because of the higher trap density in the depletion region. The larger donor and acceptor concentrations lead to a larger BBT current of p-on-n device.