A Novel Route to Colloidal InSb Quantum Dots

Abstract

The III-V semiconductor material InSb has an unusually large exciton Bohr radius (viz., 60 nm). Therefore, InSb quantum dots can be strongly quantum confined at larger sizes than most semiconductors. This allows their band gap to be tuned across a broad range of energies spanning from the mid- to the near-infrared. Consequently, InSb quantum dots are a promising material for application in devices such as infrared detectors and quantum dot solar cells. However, despite their great potential, the colloidal synthesis of InSb quantum dots is still severely underdeveloped. Existing preparation routes rely on the synthesis of the precursor compounds through elaborate methods. In this thesis, a novel synthesis route to colloidal InSb quantum dots is presented in which exclusively commercially available precursors are used. By in situ formation of a single-source precursor we were able to synthesize highly crystalline and stoichiometric colloidal InSb quantum dots. We determined the size-dependence of the InSb quantum dot band gap using steady-state near-infrared absorption spectroscopy. Transient absorption and photoluminescence spectroscopic measurements indicated that charge carriers in InSb quantum dots are quickly localized at trap states.