Fabrication of Schottky barrier diodes using H_2O_2-treated non-polar ZnO (1010) substrates

摘要

Non-polar single crystal ZnO (1010) substrates with hydrogen peroxide (H_2O_2) treatment were characterized and applied to Schottky barrier diodes. Formation of a ZnO_2 layer with a polycrystalline structure was confirmed by 26 scans of X-ray diffraction (XRD) measurements. Tails of the X-ray rocking curve of ZnO (1010) planes were broadened with increase in H_2O_2 treatment time. Grain structures were clearly observed on the surfaces of ZnO (1010) substrates with H_2O_2 treatment by an atomic force microscope, and the root mean square roughness of the ZnO_2 surface was about 5 nm. The current density-voltage (J-V) characteristics of Pd/ZnO/Al structures using ZnO (1010) substrates without H_2O_2 treatment were ohmic. The J-V characteristics of Pd/ZnO_2/ZnO/Al structures using ZnO (1010) substrates with H_2O_2 treatment time of 5 min showed good rectifying characteristics. The ideality factor n of this diode was 1.7 and the barrier height between Pd films and the ZnO_2 layer on the ZnO (1010) plane was estimated to be 0.92 eV.