Energetic Sulfide Vapor‐Processed Colloidal InAs Quantum Dot Solids for Efficient Charge Transport and Photoconduction

Abstract

The energetic sulfide vapor process on colloidal indium arsenide (InAs) quantum dots (QDs) for integrated optoelectronic devices is demonstrated. X‐ray photoemission spectroscopy supports the presence of sulfur on QD surface, which increases the air stability, and ultraviolet photoemission spectroscopy and field‐effect transistor analysis confirm n‐type charge transport of corresponding QD films with higher electron mobilities. Photoconductivity of the same devices in near‐infrared wavelength shows gate bias‐dependent recombination of photogenerated carriers, coming from charge accumulation and depletion transition of QD channels. The synergetic approach of the vapor process on colloidal QD solids opens a promising opportunity for scalable and complementary metal‐oxide semiconductor‐compatible optoelectronic devices.

Development of Group III–V Colloidal Quantum Dots for Optoelectronic Applications

“…58,68 Gas-phase deposition of chalcogenide atoms on the surface of CQDs is another prospectively powerful method that can increase the mobility with better surface passivation (Figure 4b). 63,69 Lastly, thin-shell passivation or shell coating with defect-tolerant materials might be the solution for effective trap passivation while maximizing charge transport.…”

“…Unless a short-ligand-based co-passivation strategy for handling fractional dangling bonds is developed, highly efficient thin-film device applications of group III–V CQDs seem elusive. Surface modification using metal halides can be effective as they can passivate the CQD surfaces as both X- and Z-type forms. , Gas-phase deposition of chalcogenide atoms on the surface of CQDs is another prospectively powerful method that can increase the mobility with better surface passivation (Figure b). , Lastly, thin-shell passivation or shell coating with defect-tolerant materials might be the solution for effective trap passivation while maximizing charge transport.…”

“…(b) Scheme of gas-phase deposition of chalcogenide atoms on group III–V CQD surface to enhance the mobility. Reprinted with permission from ref . Published by Wiley-VCH 2022.…”

Chemically and Electronically Active Metal Ions on InAs Quantum Dots for Infrared Detectors

“…24 Hydrogen sul de vapor treatment of InAs QD lms can also tune the electrical properties and improve their stability in air. 25 These additional ions are chemically adsorbed on the surface of the QDs and act as electrical dopants. However, there have been insu cient methodological studies to improve the properties of InAs QDs during the synthesis process.…”

High-Affinity Ligand-Enhanced Passivation of Group III–V Colloidal Quantum Dots for Sensitive Near-Infrared Photodetection

“…Short-chain thiol ligands, such as mercaptoethanol and 1,2-ethanedithiol, passivate the As dangling bonds by establishing strong As−S bonds; however, many In dangling bonds remain. 23,24 To enhance the In-site passivation, attempts have been conducted to lift-off insulating metal oxide compounds and original ligands from the surface of CQDs by treating them with strong acids, such as nitrosyl tetrafluoroborate and hydrogen chloride; 17,25,26 however, these approaches damage the surface of CQDs and distort their optical properties. Recently, an indium bromide amphoteric ligand that can dissociate into X-type (Br − ) and Z-type (InBr 2+ ) ligands has been introduced for efficiently passivating the In-rich and As-rich facets, respectively.…”