Interface states in PbSnTe/PbTeS heterodiodes

Abstract

Lattice matched heterostructure diodes (HD) p-Pb_0.8Sn_0.2Te/n-PbTe_0.97S_0.03 have been prepared by the vapour phase epitaxy (VPE) method. The diodes have a 50% spectral cutoff at λ ≅11.0 μm when operated at 82 K. Current-voltage (fI-U) and capacitance-voltage (C-U) characteristics were measured as a function of temperature. The C-U curves display peculiarities at forward bias which were explained by the existence of deep defect states localized at the interface. The best HD have R₀A product values as high as 20 Ω cm² at 77 K.