Photoconductivity of few-layered p-WSe2 phototransistors via multi-terminal measurements

Nihar R. Pradhan, Carlos Garcia, Joshua Holleman, Daniel Rhodes, Chason Parker, Saikat Talapatra, Mauricio Terrones, Luis Balicas, Stephen A. McGill

Research output: Contribution to journalArticle

10 Scopus citations

Abstract

Recently, two-dimensional materials and in particular transition metal dichalcogenides (TMDs) have been extensively studied because of their strong light-matter interaction and the remarkable optoelectronic response of their field-effect transistors (FETs). Here, we report a photoconductivity study from FETs built from few-layers of p-WSe2 measured in a multi-terminal configuration under illumination by a 532 nmlaser source. The photogenerated current was measured as a function of the incident optical power, of the drain-to-source bias and of the gate voltage. We observe a considerably larger photoconductivity when the phototransistors were measured via a four-terminal configuration when compared to a two-terminal one. For an incident laser power of 248 nW, we extract 18 A W-1 and ∼4000% for the two-terminal responsivity (R) and the concomitant external quantum efficiency (EQE) respectively, when a bias voltage Vds = 1 Vand a gate voltage Vbg = 10 Vare applied to the sample. R and EQE are observed to increase by 370% to ∼85 A W-1 and ∼20 000% respectively, when using a four-terminal configuration. Thus, we conclude that previous reports have severely underestimated the optoelectronic response of transition metal dichalcogenides, which in fact reveals a remarkable potential for photosensing applications.

Original languageEnglish (US)
Article number041004
Journal2D Materials
Volume3
Issue number4
DOIs
StatePublished - Oct 14 2016

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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    Pradhan, N. R., Garcia, C., Holleman, J., Rhodes, D., Parker, C., Talapatra, S., Terrones, M., Balicas, L., & McGill, S. A. (2016). Photoconductivity of few-layered p-WSe2 phototransistors via multi-terminal measurements. 2D Materials, 3(4), [041004]. https://doi.org/10.1088/2053-1583/3/4/041004