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During the last few years, there was increasing interest in oxide p-n junctions formed between hole-doped colossal magnetoresistance manganites and n-type conducting SrTiO3. Magnetic field-dependent nonlinear electrical properties and rectifying behavior have been reported. Semiconductor p-n junction is known to be a basic element of various semiconductor devices. Thus, we point a promising possibility to combine functional properties of the manganites with Si electronics. Till now, there have been only a few reports on the fabrication of the heterostructures based on perovskite manganites and Si. Here in this work, we report fabrication and investigation of the p-n junctions, composed of p-type La2/3Sr1/3MnO3 (LSMO), La2/3Ca1/3MnO3 (LCaMO) and La2/3Ba1/3MnO3 (LBMO) thin films grown on n-type Si(001) wafers with resistivity of 0.1- 5.0 Ωcm. Before film deposition, Si substrates were dipped into a 5% HF solution to remove the native silicon oxide and subsequently transferred into the vacuum chamber. The LBMO, LCaMO and LSMO thin films of polycrystalline quality were grown in-situ at 750°C by pulsed laser deposition and dc magnetron sputtering. The junction resistance, Rj, magnetoresistance, MRj, and current-voltage (I-U) characteristics were measured for the LBMO/Si, LSMO/Si, and LCMO/Si heterojunctions over a wide temperature region (77–300 K) by passing current perpendicular to a film plane. All the prepared heterojunctions displayed clearly defined asymmetric I-U relations and photocarrier injection effect. The diffusion voltage, VD, estimated for the heterojunctions in a case of a forward bias was found to decrease with increasing temperature. The highest MRj, values were indicated for the LBMO/Si heterojunctions at T<200 K. Formation of the interface during film growth and postdeposition annealing were found to be of key importance for major electrical parameters of the heterojunctions. |