PROPERTIES OF P-PBTE (GA) BASED DIODE STRUCTURES

Single crystals of p-PbTe(Ga) with gallium density too low for complet e compensation of uncontrollable impurities and intrinsic lattice defe cts and realization of Fermi level (FL) pinning were investigated for the purpose of producing diode structures In contact-[p-PbTe(Ga)]-Pt c ontact. It was found that the properties of the structures obtained ha ve a number of features that distinguish them from In-[p-PbTe] Schottk y barriers. The current-voltage characteristics (IVCs) of the experime ntal structures are not described by the standard relation of the Scho ttky theory not only in the region of reverse bias but also in the reg ion of direct bias. Residual photoconductivity (PC) is observed under illumination with a thermal radiation source in the temperature range T<80 K; after the illumination is switched off, the IVCs are linear. U nder constant illumination a photo-emf appears and the branches of the IVCs in the region of reverse biases rectify. The experimental result s are discussed on the basis of the assumption that regions with n-typ e conductivity form and FL stabilizes near the nonohmic contact as a r esult of band bending. It has not been ruled out that n-PbTe(Ga) regio ns are initially present in the sample, but they are not manifested un der ohmic contact conditions. (C) 1997 American Institute of Physics. [S1063-7826(97)01811-5].