A simple method is introduced for the preparation of large-area films of molybdenum trioxide （MoO3） microbelts. It is found that such films can be grown on indium tin oxide （ITO） glasses or silicon substrates at low temperatures by thermal evaporation deposition in air without using catalyst. Field emission measurements show that the turn-on field of the MoO3 microbelts is as low as 2.2 V/μm required to obtain a current density of 10 μA/cm^2, The combination of the simplicity of the growth method and the attractive field emission performance makes it a potential low-cost technique for the preparation of large-area field emission cold cathode material.
Dongmei Ban,Ningsheng Xu,Shaozhi Deng,Jun Chen and Juncong She State Key Lab of Optoelectronic Materials and Technologies,Guangdong Province Key Laboratory of Display Material and Technology,School of Physics and Engineering,Sun Yat-sen University,Guangzhou 510275,China
Nanodevices using the photovoltaic effect of a single nanowire have attracted growing interest. In this paper, we consider potential applications of the photovoltaic effect to optical signal coupling and optical power transmission, and report on the realization of a heterojunction formed between WO2 and WO3 in a fine-wire having a diameter on the micrometer scale. Using a laser beam of 514.5 nm as a signal source, the WO2-WO3 heterojunction yields a maximum output power of up to 37.4 pico watt per heterojunction. Fast responses （less than a second） of both photovoltaic voltage and current are also observed. In addition, we demonstrate that it is a simple and effective way to adapt a commercial Raman spectrometer for the combined functions of fabrication, material characterization and photovottaic measurement of an optical signal coupler and optical power transmitter based on a fine-wire. Our results show an attractive perspective of developing nanowire or fine-wire elements for coupling optical signals into and for powering a nanoelectronic or nano-optoelectronic integrated circuit that works under the condition of preventing it from directly electrically connecting with the optical coupler.
