Lead telluride p-n junctions for infrared detection:: Electrical and optical characteristics

PbTe mesa diodes were fabricated from a series of p-n junctions grown on BaF2 substrates. For this series, the hole concentration was kept constant at 10(17) cm(-3) and the electron concentration varied between and 10(19) cm(-3). Capacitance versus voltage analysis revealed that for n > 10(18) cm(-3), a one-sided abrupt junction is formed. The direct and reverse branches of the current versus voltage curves exhibited different forms among the diodes. The R(0)A product varied between 0.23 and 31.8 Omega cm(2), and the integral detectivity ranged from 1.1 x 10(8) to 6.5 x 10(10) cmHz(1/2)W(-1). The performance of the best PbTe photodiodes fabricated here is comparable to the commercial InSb and HgCdTe infrared detectors, and to the PbTe sensors grown on Si substrate.