Preparation and characterization of La0.5Sr0.5CoO3/Al-doped ZnO thin film heterojunctions

In this study, p-n heterojunctions with La0.5Sr0.5CoO3 (LSCO) and Al-doped ZnO (AZO) thin films were fabricated by the radio frequency (r.f.) magnetron sputtering technique. The LSCO/AZO heterojunction was obtained by stacking the p-type LSCO thin film on the annealed n-type AZO thin film under different Ar:O-2 sputter gas ratio atmosphere. The thickness of LSCO and AZO thin films are about 400 nm and 500 nm, respectively. Good crystalline match between LSCO and AZO films was observed from the SEM and XRD analysis. The heterojunction diode clearly demonstrated rectifying behavior in the range of 8 to +8 V in reverse shape. The turn-on voltage of the diodes is obtained around 1.5 V and is in agreement with the value obtained from the difference in the work functions of ISCO and AZO. The band structure of the heterojunction was proposed based on the results of analysis. (C) 2011 Elsevier Ltd. All rights reserved.