Investigation of the Self‐Doping Process in HgSe Nanocrystals

Abstract

Colloidal nanocrystals are an interesting platform for the design of low cost infrared optoelectronic materials. In addition to the conventionally observed interband features, doped nanocrystals present intraband transitions, which expand the possibilities for electronic spectrum engineering. In this paper, the recent results obtained in the field of mercury chalcogenides self-doped nanocrystals presenting absorption features in the mid infrared range are reviewed. In particular, the results relative to the synthesis, control of doping and transport properties of HgSe colloidal nanocrystals are discussed.

Colloidal quantum dots for thermal infrared sensing and imaging

“…A specific detectivity of 10 8 Jones was measured at room temperature, which is comparable to the performance of commercial deuterated triglycine sulfate (DTGS) detectors, with 1/f noise being the dominant noise mechanism. Optimized doping is of upmost importance in realizing high performance devices and has been discussed in various literatures [50, 70, 71] CQD films, after ligand-exchange, typically show modification in carrier concentration which is largely attributed to the bending/shifting in the energy level due to ligand-induced surface dipoles; when the 1S e energy level is lower than O 2 /H 2 O redox potential, water acts as a reducing agent, making CQDs electron-rich in the ambient [50]. This theory is also consistent with the observation that intraband absorbance decreases with decreasing CQD size (stronger quantum confinement and thus, higher energy level position with respect to O 2 /H 2 O redox potential).…”

Mercury chalcogenide colloidal quantum dots for infrared photodetection: from synthesis to device applications

“…Meanwhile, intra-band photodetection using other Hg chalcogenide QDs is promising for longer wavelength absorption with smaller dots. 13 Although these QDs contain heavy metal Hg, the Hg content in the thin-film based Hg chalcogenide QD photodetectors is very low and is sequestered in the form of a covalently bound material rather than volatile free metal or soluble leachable ionic compounds.…”