( Invited ) Evolution of Intraband Transitions of Self-Doped Metal Chalcogenides Colloidal Quantum Dots

Abstract

Wavelength-tunable infrared nanocrystals with non-regulated substances are of great interest in next-generation semiconductor optoelectronics. To meet the regulation criteria, it is imperative to avoid using toxic elements such as Pb, well-known materials for high-performance infrared semiconductors. Silver chalcogenide Ag 2 E (E=Se, Te) semiconductors with narrow bandgap energy are excellent candidates for the alternative to toxic infrared materials. Additionally, as the large exciton Bohr radius allows the silver chalcogenides quantum dots (QDs) to widely tune the electronic transition energy of the material. Beyond the band-to-band transition, it is possible to fill the lowest conduction band state of the QD under particular conditions, leading to the intraband transition in a steady state. In this talk, I will present the self-doped and undoped Ag 2 E QDs with a widely tunable wavelength and selective electronic transitions. Self-doping allows us to selectively use either the bandgap transition or intraband transition, which is the unique property of quantum dots. With the self-doped and undoped Ag 2 E QDs, we prepared the mid-wavelength and short-wavelength infrared CQD inks and fabricated infrared QD photodetectors.