Fabrication of Schottky barrier diodes using H2O2-treated non-polar ZnO 1 0 1 ¯0 substrates

• Published in: Applied surface science 2013-12, Vol.286, p.126-130
• Main Authors: Kashiwaba, Yasuhiro, Sakuma, Mio, Abe, Takami, Nakagawa, Akira, Niikura, Ikuo, Kashiwaba, Yasube, Daibo, Masahiro, Osada, Hiroshi
• Format: Article
• Language: English
• Subjects: Non-polar; Schottky contact; Surface treatment; ZnO; ZnO2
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2013.09.034

•We characterized non-polar single crystal ZnO 1 0 1 ¯0 substrates with H2O2 treatment.•A ZnO2 layer was formed on single crystal ZnO 1 0 1 ¯0 substrates with H2O2 treatment.•The contact between Pd and surface of H2O2-treated ZnO 1 0 1¯ 0 substrates showed rectifying characteristics.•The Schottky characteristics improved with increase in H2O2 treatment time. Non-polar single crystal ZnO 1 0 1¯ 0 substrates with hydrogen peroxide (H2O2) treatment were characterized and applied to Schottky barrier diodes. Formation of a ZnO2 layer with a polycrystalline structure was confirmed by 2θ scans of X-ray diffraction (XRD) measurements. Tails of the X-ray rocking curve of ZnO 1 0 1¯ 0 planes were broadened with increase in H2O2 treatment time. Grain structures were clearly observed on the surfaces of ZnO 1 0 1 ¯0 substrates with H2O2 treatment by an atomic force microscope, and the root mean square roughness of the ZnO2 surface was about 5nm. The current density–voltage (J–V) characteristics of Pd/ZnO/Al structures using ZnO 1 0 1 ¯0 substrates without H2O2 treatment were ohmic. The J–V characteristics of Pd/ZnO2/ZnO/Al structures using ZnO 1 0 1 ¯0 substrates with H2O2 treatment time of 5min showed good rectifying characteristics. The ideality factor n of this diode was 1.7 and the barrier height between Pd films and the ZnO2 layer on the ZnO 1 0 1 ¯0 plane was estimated to be 0.92eV.