This report describes our efforts to fabricate InAsP/InAs and InAsPSb/InAs epitaxial diode heterostructures for TPV converter applications. For the growth of these TPV-structurcs the new version of liquid-phase electroepitaxy has been employed. First type of structure consists of the n-InAs (111)B substrate and compositionally graded p-InAsP layer with the increasing concentration of phosphorus from impurity levels up to 6%, along the growth direction. The second type of structure consists of p-InAsPSb layer directly grown on a n-InAs (100) substrate. These structures have a uniform thickness, a mirror-like surface and a very flat interface. The dislocation density on the surface layer was no more than N-D = 10(5) cm(-2). The I-V and C-V characteristics of n-InAs/p-InAsP and n-InAs/p-InAsPSb TPV structures have been investigated. The spectral response of these diode structures has been measured. The results of these studies show that the second type of TPV structures has better performance than the first type. (C) 2003 Elsevier B.V. All rights reserved.