Zn-doped P-type InAs Nanocrystal Quantum Dots

TL;DR

This paper demonstrates successful p-type doping of InAs nanocrystals with zinc, enabling control over charge carriers and improving near-infrared emission for potential IR optoelectronic applications.

Contribution

It introduces a novel post-synthesis doping method for InAs nanocrystals using zinc, with detailed analysis of the doping mechanism and enhanced optical properties.

Findings

Successful p-type doping achieved with diethylzinc

Zn substitution confirmed by X-ray absorption spectroscopy

Enhanced near IR photoluminescence observed

Abstract

Doped heavy metal-free III-V semiconductor nanocrystal quantum dots are of great interest both from the fundamental aspects of doping in highly confined structures, and from the applicative side of utilizing such building blocks in the fabrication of p-n homojunction devices. InAs nanocrystals, that are of particular relevance for short wave IR detection and emission applications, manifest heavy n-type character poising a challenge for their transition to p-type behavior. We present p-type doping of InAs nanocrystals with Zn-enabling control over the charge carrier type in InAs QDs field effect transistors. The post-synthesis doping reaction mechanism is studied for Zn precursors with varying reactivity. Successful p-type doping was achieved by the more reactive precursor, diethylzinc. Substitutional doping by Zn2+ replacing In3+ is established by X-ray absorption spectroscopy analysis. Furthermore, enhanced near IR photoluminescence is observed due to surface passivation by Zn as indicated from elemental mapping utilizing high resolution electron microscopy corroborated by X-ray photoelectron spectroscopy study. The demonstrated ability to control the carrier type, along with the improved emission characteristics, paves the way towards fabrication of optoelectronic devices active in the short wave IR region utilizing heavy-metal free nanocrystal building blocks.