pn‐Heterojunction Diodes with n‐Type In₂O₃

Abstract

pn‐Heterodiodes comprising the wide bandgap semiconducting oxide In 2 O 3 and amorphous p‐conducting NiO or ZnCo 2 O 4 are realized. In 2 O 3 is grown at 600 °C and the amorphous p‐type oxides at room temperature by pulsed‐laser deposition. Highest rectification of about four orders of magnitude is observed for structures with Mg‐doped In 2 O 3 layers having lower carrier density than undoped layers. The p‐ZnCo 2 O 4 /n‐In 2 O 3 diodes do not show degradation at elevated temperatures of 150 °C, whereas the p‐NiO/n‐In 2 O 3 diodes degrade irreversibly for T > 100 °C. Thermal admittance spectroscopy revealed shallow defect levels in the In 2 O 3 layer with activation energy of about 12 and 250 meV, respectively.