STUDY OF p-n JUNCTIONS BASED ON LANTHANUM MANGANITES
|Renata Butkute 1, Bonifacas Vengalis 1,3, Jelena Devenson 1, Fiodoras Anisimovas 1, Antanas Oginskis 1, Alexandra M. Rosa 2|
1. Semiconductor Physics Institute, A.Gostauto 11, Vilnius LT-2600, Lithuania
In this work, we present the results of growth and investigation of p-n diode structures based on hole-doped lanthanum manganite films. High crystalline quality p-type La2/3A1/3MnO3 (A = Ba, Ca and Ce) thin films were grown heteroepitaxially by pulsed laser deposition and magnetron sputtering onto conductive n-type SrTiO3:Nb (STON) substrates. X-ray diffraction measurements demonstrated perfect crystalline structure of the prepared LBMO and LCaMO films, while traces of CeO2 as a secondary phase have been indicated for the LCeMO films. Resistance versus temperature curves measured for the films with current in-plane geometry were compared to zero field temperature-dependent junction resistance of the p-n structures. The current-voltage characteristics of all the structures exhibited a rectifying behaviour similar to p-n diode with the characteristic barrier voltage in a case of forward bias increasing gradually from about 0.25 V at 300 K to 0.8 V at 78 K. Special attention was focussed on a comparative study of nonlinear current-voltage characteristics, magnetoresistance and photoconductivity of the prepared diode structures. Various heterostructures were annealed at different temperatures under various oxygen pressure conditions. The observed thermal instability of the LCaMO/STON and LCeMO/STON interfaces was associated with formation of high resistance region (tunnel barrier) due to a diffusion of oxygen ions under strong internal electrical field and possible phase separation in the manganite films at the interface.
Presentation: poster at E-MRS Fall Meeting 2005, Symposium F, by Renata Butkute
See On-line Journal of E-MRS Fall Meeting 2005
Submitted: 2005-05-30 13:36 Revised: 2009-06-07 00:44