| AVS 63rd International Symposium & Exhibition | |
| 2D Materials Focus Topic | Wednesday Sessions |
| Session 2D+TF-WeM |
| Session: | 2D Materials: Growth and Fabrication |
| Presenter: | Avra S. Bandophadyay, University of Texas at El Paso |
| Authors: | A.S. Bandophadyay, University of Texas at El Paso G.A. Lara Saenz, University of Texas at El Paso C. Biswas, University of Texas at El Paso A.B. Kaul, University of Texas at El Paso |
| Correspondent: | Click to Email |
Semiconducting Transition Metal Dichalcogenides (TMDCs) have attracted a lot of attention recently, because of their interesting electronic, optical, and mechanical properties [1]. Among large numbers of TMDCs, monolayers of tungsten diselenides (WSe2) are of particular interest since WSe2 possesses a direct band gap (~1.6eV) and tunable charge transport behavior, which makes it suitable for a variety of electronic and optoelectronic applications. Direct synthesis of large domains of monolayer WSe2 and their growth mechanism studies are important steps toward applications of WSe2. In this work, we have synthesized Tungsten Diselenide via Chemical Vapor Deposition Method using WO3 powder and Se pellets as the precursors. Selenium was placed at the upstream side of the furnace at a temperature zone of 260-270oC. The temperatures and distances of these two sources were carefully controlled and adjusted. We used silicon with 300 nm thermally grown SiO2 as the substrate and it was placed at some distance from the WO3 source. The substrates for growing WSe2 are put at the downstream side, where the Se and WO3 vapors were brought to the targeting substrates by an Ar/H2 (4:1) flowing gas with a flow rate of 120sccm. The pressure was maintained at 5Torr throughout the experiment. The temperatures at the Se source, WO3 source and Substrates are maintained 260oC, 950oC and 750-850oC respectively. After the growth, the temperature of the furnace was naturally cooled down to room temperature and the samples were taken out for characterization. The size and shape of the as-grown flakes were observed under an Optical Microscope. Raman spectroscopy was used to determine the number of layers by noting the location of the Raman peaks and the relative Raman shift. In this paper we will discuss our work on the synthesis and characterization of 2D WSe2, where we have also succeeded in forming monolayer structures for electronic device applications.
References:
[1] A. B. Kaul, Journal of Materials Research, vol. 29, pp. 348-361, 2014.
[2] H.Sahin et al, Physics Review B, vol. 87, pp. 1654091-1654096, 2013.