High quality La2/3Ba1/3MnO3 (LBMO), La2/3Ca1/3MnO3 (LCaMO) and La2/3Ce1/ 3MnO3 (LCeMO) thin films were grown on Nb 0.1 wt.% doped conducting SrTiO3(100) (STON) substrates. Asymmetric current-voltage relations measured for the LBMO/STON, LCaMO/STON and LCeMO/STON heterostructures at T=78/300 K certified hole-doping of the manganite films. The diffusion voltage, corresponding to a steep current increase at forward bias has been estimated. The LCaMO/STON heterojunction showed possible impact of interfacial strain on the rectifying behavior, meanwhile, the LaCeMO/STON heterostructures demonstrated evidence of phase separation of the manganite film at the interface. (c) 2006 Elsevier B.V. All rights reserved.