P-Type Doping of WS2 Quantum Dots via Pulsed Laser Ablation

Septem P. Caigas, Min Chiang Cheng, Tzu Neng Lin, Svette Reina Merden S. Santiago, Chi Tsu Yuan, Chun Chuen Yang, Wu-Ching Chou, Ji Lin Shen*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

19 Scopus citations


Doping provides an advantage to engineering the optical and electrical characteristics of transition-metal dichalcogenides (TMDs). Here, we report the doping of WS2 quantum dots (QDs) with diethylenetriamine (DETA) using pulsed laser ablation. The synthesized DETA-doped 2H-WS2 QDs with an average size of ∼6 nm have been demonstrated by transmission electron microscopy. With the introduction of DETA during pulsed laser ablation, current modulation, carrier concentration, and field-effect mobility are greatly enhanced, demonstrating a successful doping in WS2 QDs. The positive shift of the threshold voltage in gate-dependent conductance measurements reveals p-type doping for DETA-doped WS2 QDs. A remarkable improvement in photoluminescence in WS2 QDs by 74-fold has been achieved after DETA doping. An anomalous dopant-dependent negative photoconductivity was observed for WS2 QDs, originating from light-induced desorbing of water (oxygen) molecules on the surface. The proposed doping approach can provide a vehicle to modulate the optical and electrical properties in WS2 QDs and could be important in the performance improvement of WS2-QD-based devices.

Original languageEnglish
Pages (from-to)4828-4837
Number of pages10
JournalACS Photonics
Issue number12
StatePublished - 19 Dec 2018


  • WS quantum dot
  • conductivity
  • doping
  • photoluminescence
  • pulsed laser ablation


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