Publication date: 15th May 2025
Thin-films of epitaxially-fused quantum dots (QDs) offer increased carrier mobilities but also introduce greater access to surface defects, limiting opportunities for optoelectronic applications. We optimize optoelectronic performance by using a post-synthesis and post-deposition colloidal atomic layer deposition (c-ALD) process that results in an all-inorganic, bandgap engineered epitaxially-fused PbSe QD/CdS matrix heterostructure. The c-ALD process progressively infills the interstitial spaces between epitaxially fused PbSe QDs to produce an encapsulating CdS matrix. Through electrical and optical measurements, we demonstrate control over carrier concentration and type in achieving p-type, n-type, and ambipolar optoelectronic devices. These c-ALD treated optoelectronic devices also feature greater environmental stability at higher temperatures and exposure to air.