Tuesday, September 6, 2016

Growth and characterization of WSe2 single crystals using TeCl4 as transport agent


•WSe2 single crystals (25–100 mm2) grown by the chemical vapor transport method.

•High quality single crystals obtained from slowly cooled polycrystalline powders.

•WSe2 single crystals with a photocurrent plateau at 75 mA cm−2.

The growth of WSe2 single crystals, using TeCl4 as transport agent was performed successfully from slowly cooled polycrystalline powders as precursors. The resulting single crystals were characterized by X-ray diffraction (XRD) and their surfaces examined by scanning electron microscopy (SEM) presented fewer defects than single crystals prepared from air-quenched polycrystalline powders. Energy Dispersive X-ray microanalysis (EDX), inductively coupled plasma (ICP) spectroscopy and X-ray photoelectron spectroscopy (XPS) revealed that the single crystals are homogeneous and stoichiometric. Electrical conductivity and photocurrent measurements have confirmed the semiconducting character of the single crystals and a photocurrent of 75 mA cm−2 has been reached. In addition, single crystals with areas in the 25–100 mm2 range can be obtained under the reported growth conditions.

Keywords:  A1. Characterization;  A1. Crystal morphology;  A2. Single crystal growth;  B1. Inorganic compounds;  B2. Semiconducting materials; B3. Solar cells

Source: Sciencedirect