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Title: Rapid, non-destructive evaluation of ultrathin WSe{sub 2} using spectroscopic ellipsometry

Abstract

The utilization of tungsten diselenide (WSe{sub 2}) in electronic and optoelectronic devices depends on the ability to understand and control the process-property relationship during synthesis. We demonstrate that spectroscopic ellipsometry is an excellent technique for accurate, non-destructive determination of ultra-thin (<30 nm) WSe{sub 2} properties. The refractive index (n) and extinction coefficient (k) were found to be independent of thickness down to 1.3 nm, and were used to determine film thickness, which was confirmed to be within 9% of values found via atomic force microscopy. Finally, the optical bandgap was found to closely correlate with thickness, ranging from 1.2 to 1.55 eV as the WSe{sub 2} is thinned to the equivalent of 2 atomic layers.

Authors:
; ;  [1];  [2];  [3];  [1];  [2];  [2]
  1. Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States)
  2. (United States)
  3. Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States)
Publication Date:
OSTI Identifier:
22303562
Resource Type:
Journal Article
Resource Relation:
Journal Name: APL Materials; Journal Volume: 2; Journal Issue: 9; Other Information: (c) 2014 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ATOMIC FORCE MICROSCOPY; CONTROL; ELLIPSOMETRY; EVALUATION; FILMS; REFRACTIVE INDEX; SYNTHESIS; THICKNESS; TUNGSTEN

Citation Formats

Eichfeld, Sarah M., Lin, Yu-Chuan, Hossain, Lorraine, Center for Two-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802, Eichfeld, Chad M., Robinson, Joshua A., E-mail: jrobinson@psu.edu, Center for Two-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802, and Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802. Rapid, non-destructive evaluation of ultrathin WSe{sub 2} using spectroscopic ellipsometry. United States: N. p., 2014. Web. doi:10.1063/1.4893961.
Eichfeld, Sarah M., Lin, Yu-Chuan, Hossain, Lorraine, Center for Two-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802, Eichfeld, Chad M., Robinson, Joshua A., E-mail: jrobinson@psu.edu, Center for Two-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802, & Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802. Rapid, non-destructive evaluation of ultrathin WSe{sub 2} using spectroscopic ellipsometry. United States. doi:10.1063/1.4893961.
Eichfeld, Sarah M., Lin, Yu-Chuan, Hossain, Lorraine, Center for Two-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802, Eichfeld, Chad M., Robinson, Joshua A., E-mail: jrobinson@psu.edu, Center for Two-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802, and Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802. Mon . "Rapid, non-destructive evaluation of ultrathin WSe{sub 2} using spectroscopic ellipsometry". United States. doi:10.1063/1.4893961.
@article{osti_22303562,
title = {Rapid, non-destructive evaluation of ultrathin WSe{sub 2} using spectroscopic ellipsometry},
author = {Eichfeld, Sarah M. and Lin, Yu-Chuan and Hossain, Lorraine and Center for Two-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802 and Eichfeld, Chad M. and Robinson, Joshua A., E-mail: jrobinson@psu.edu and Center for Two-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802 and Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802},
abstractNote = {The utilization of tungsten diselenide (WSe{sub 2}) in electronic and optoelectronic devices depends on the ability to understand and control the process-property relationship during synthesis. We demonstrate that spectroscopic ellipsometry is an excellent technique for accurate, non-destructive determination of ultra-thin (<30 nm) WSe{sub 2} properties. The refractive index (n) and extinction coefficient (k) were found to be independent of thickness down to 1.3 nm, and were used to determine film thickness, which was confirmed to be within 9% of values found via atomic force microscopy. Finally, the optical bandgap was found to closely correlate with thickness, ranging from 1.2 to 1.55 eV as the WSe{sub 2} is thinned to the equivalent of 2 atomic layers.},
doi = {10.1063/1.4893961},
journal = {APL Materials},
number = 9,
volume = 2,
place = {United States},
year = {Mon Sep 01 00:00:00 EDT 2014},
month = {Mon Sep 01 00:00:00 EDT 2014}
}