Trap-induced photoresponse of solution-synthesized MoS2

Youngbin Lee, Jaehyun Yang, Dain Lee, Yong Hoon Kim, Jin Hong Park, Hyoungsub Kim, Jeong Ho Cho

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

We investigated, for the first time, the photoresponse characteristics of solution-synthesized MoS2 phototransistors. The photoresponse of the solution-synthesized MoS2 phototransistor was solely determined by the interactions of the photogenerated charge carriers with the surface adsorbates and the interface trap sites. Instead of contributing to the photocurrent, the illumination-generated electron-hole pairs were captured in the trap sites (surface and interface sites) due to the low carrier mobility of the solution-synthesized MoS2. The photogenerated holes discharged ions (oxygen and/or water) adsorbed onto the MoS2 surface and were released as neutral molecules. At the same time, the photogenerated electrons filled the traps present at the interface with the underlying substrate during their transport to the drain electrode. The filled trap sites significantly relieved the band bending near the surface region, which resulted in both a negative shift in the turn-on voltage and an increase in the photocurrent. The time-dependent dynamics of the solution-synthesized MoS2 phototransistors revealed persistent photoconductance due to the trapped electrons at the interface. The photoconductance was recovered by applying a short positive gate pulse. The instantaneous discharge of the trapped electrons dramatically reduced the relaxation time to less than 20 ms. This study provides an important clue to understanding the photoresponses of various optoelectronic devices prepared using solution-synthesized two-dimensional nanomaterials.

Original languageEnglish
Pages (from-to)9193-9200
Number of pages8
JournalNanoscale
Volume8
Issue number17
DOIs
Publication statusPublished - 2016 May 7

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Phototransistors
Electrons
Photocurrents
Carrier mobility
Beam plasma interactions
Adsorbates
Charge carriers
Nanostructured materials
Optoelectronic devices
Relaxation time
Lighting
Ions
Oxygen
Electrodes
Molecules
Water
Electric potential
Substrates

All Science Journal Classification (ASJC) codes

  • Materials Science(all)

Cite this

Lee, Y., Yang, J., Lee, D., Kim, Y. H., Park, J. H., Kim, H., & Cho, J. H. (2016). Trap-induced photoresponse of solution-synthesized MoS2 Nanoscale, 8(17), 9193-9200. https://doi.org/10.1039/c6nr00654j
Lee, Youngbin ; Yang, Jaehyun ; Lee, Dain ; Kim, Yong Hoon ; Park, Jin Hong ; Kim, Hyoungsub ; Cho, Jeong Ho. / Trap-induced photoresponse of solution-synthesized MoS2 In: Nanoscale. 2016 ; Vol. 8, No. 17. pp. 9193-9200.
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Lee, Y, Yang, J, Lee, D, Kim, YH, Park, JH, Kim, H & Cho, JH 2016, 'Trap-induced photoresponse of solution-synthesized MoS2 ', Nanoscale, vol. 8, no. 17, pp. 9193-9200. https://doi.org/10.1039/c6nr00654j

Trap-induced photoresponse of solution-synthesized MoS2 . / Lee, Youngbin; Yang, Jaehyun; Lee, Dain; Kim, Yong Hoon; Park, Jin Hong; Kim, Hyoungsub; Cho, Jeong Ho.

In: Nanoscale, Vol. 8, No. 17, 07.05.2016, p. 9193-9200.

Research output: Contribution to journalArticle

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Lee Y, Yang J, Lee D, Kim YH, Park JH, Kim H et al. Trap-induced photoresponse of solution-synthesized MoS2 Nanoscale. 2016 May 7;8(17):9193-9200. https://doi.org/10.1039/c6nr00654j