We have fabricated different heterojunctions by pulsed laser depositing different thickness films of TbMnO3(TMO) on single crystal Nb-1.0 wt.%-doped SrTiO3 substrates. In addition to all those heterojunctions showing good rectifying properties, the most interesting phenomena are thickness-dependent backward diodelike behavior at low temperatures. Especially, when TMO film thickness is 40 run, the normal diodelike behavior are found in a wide temperature range from 25 to 350 K, and the rectifying behaviors are nearly independent of temperature below 300 K. When TMO film thickness is 60 run, the backward rectifying behaviors are nearly independent of temperature below 200 K. This work implies that various rectifying properties can be gotten in the same manganite based diodes by controlled different parameters. (c) 2007 Elsevier B.V. All rights reserved.