Vacuum and Surface Science, 65(9) 388-393, Sep 10, 2022 Peer-reviewed
Copper oxide nanowires with good crystallinity and high aspect ratio have been attractive for use in high-performance optical and electronic devices. In this work, we fabricated copper oxide nanowires by thermal oxidation method. Copper oxide nanowires were fabricated at various heating times, keeping at a heating temperature of 500℃. When the heating time was over 30 minutes, the average width of the nanowires reached about 100 nm. It was observed that the bottom part of the nanowire was thick compared to the top part. We investigated the detailed structure by using micro-raman spectroscopy and electron backscatter diffraction (EBSD). From the results of raman spectra and EBSD crystal orientation mappings, it was found that Cu2O/CuO heterostructure is formed at the thick region of the nanowire. Two type of heterostructures were confirmed, namely Cu2O(110)/CuO(001) and Cu2O(110)/CuO(110).
Japanese Journal of Applied Physics, 61(8) 086504-086504, Jul 27, 2022 Peer-reviewed
Abstract
The chemical vapor transport method was used in this research to synthesize MoS2 bulk. Through mechanical exfoliation, we limited the thickness of MoS2 flakes from 1 to 3 μm. In order to fabricate a p–n homogeneous junction, we used oxygen plasma treatment to transform the MoS2 characteristics from n-type to p-type to fabricate a p–n homogenous junction and demonstrate the charge neutrality point shift from −80 to +102 V successfully using FET measurement. The MoS2 p–n homogeneous junction diode showed an excellent p-n characteristic curve during the measurements and performed great rectifying behavior with 1–10 Vpp in the half-wave rectification experiment. This work demonstrated that MoS2 flake had great potential for p-n diodes that feature significant p–n characteristics and rectifying behavior.
We report on the field electron emission from pillar array of carbon nanotube bundles grown by thermal chemical vapor deposition. The emission of a current density of 150mA/cm^2 at a DC electric field of 1.6V/μm exhibited good stability without degradation for 200 hours. Decrease and full recovery in emission current was observed when operating upon oxygen exposure and subsequently heating at an ultrahigh vacuum, which can be explained by work function change. These robust and regenerable emission properties are attributed to the aligned and high-density structure of the carbon nanotube bundles.
We investigated the effect of electrical aging on field electron emission from a screen printed carbon nanotube (CNT) film. After maintaining the field emission of 20mA/cm^2 for 3h in DC mode, it was observed that relatively long CNTs were shortened and lying CNTs were standing up. As a result, the number of hot spots in fluorescence screen was decreased and the field emission uniformity was remarkably improved due to the increase in the number of the emission sites. Furthermore, after electrical aging, the emission current became more stable and the lifetime property was improved.