General Synthetic Route to High-Quality Colloidal III-V Semiconductor Quantum Dots Based on Pnictogen Chlorides

Abstract

The synthesis of colloidal III-V quantum dots (QDs), particularly of the arsenides and antimonides, has been limited by the lack of stable and available group V precursors. In this work, we exploit accessible InCl3- and pnictogen chloride-oleylamine as precursors to synthesize III-V QDs. Through coreduction reactions of the precursors, we achieve size- and stoichiometry-tunable binary InAs and InSb as well as ternary alloy InAs1-xSbx QDs. On the basis of structural, analytical, optical, and electrical characterization of the QDs and their thin-film assemblies, we study the effects of alloying on their particle formation and optoelectronic properties. We introduce a hydrazine-free hybrid ligand-exchange process to improve carrier transport in III-V QD thin films and realize InAs QD field-effect transistors with electron mobility > 5 cm2/(V s). We demonstrate that III-V QD thin films are promising candidate materials for infrared devices and show InAs1-xSbx QD photoconductors with superior short-wavelength infrared (SWIR) photoresponse than those of the binary QD devices.