Towards zero-threshold optical gain using charged semiconductor quantum dots

Kaifeng Wu, Young Shin Park, Jaehoon Lim, Victor I Klimov

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

Colloidal semiconductor quantum dots are attractive materials for the realization of solution-processable lasers. However, their applications as optical-gain media are complicated by a non-unity degeneracy of band-edge states, because of which multiexcitons are required to achieve the lasing regime. This increases the lasing thresholds and leads to very short optical gain lifetimes limited by nonradiative Auger recombination. Here, we show that these problems can be at least partially resolved by employing not neutral but negatively charged quantum dots. By applying photodoping to specially engineered quantum dots with impeded Auger decay, we demonstrate a considerable reduction of the optical gain threshold due to suppression of ground-state absorption by pre-existing carriers. Moreover, by injecting approximately one electron per dot on average, we achieve a more than twofold reduction in the amplified spontaneous emission threshold, bringing it to the sub-single-exciton level. These measurements indicate the feasibility of 'zero-threshold' gain achievable by completely blocking the band-edge state with two electrons.

Original languageEnglish
Pages (from-to)1140-1147
Number of pages8
JournalNature Nanotechnology
Volume12
Issue number12
DOIs
Publication statusPublished - Jan 1 2017

Fingerprint

Optical gain
Semiconductor quantum dots
quantum dots
thresholds
lasing
Electrons
Spontaneous emission
Excitons
Ground state
spontaneous emission
electrons
Lasers
excitons
retarding
life (durability)
ground state
decay
lasers

ASJC Scopus subject areas

  • Bioengineering
  • Atomic and Molecular Physics, and Optics
  • Biomedical Engineering
  • Materials Science(all)
  • Condensed Matter Physics
  • Electrical and Electronic Engineering

Cite this

Towards zero-threshold optical gain using charged semiconductor quantum dots. / Wu, Kaifeng; Park, Young Shin; Lim, Jaehoon; Klimov, Victor I.

In: Nature Nanotechnology, Vol. 12, No. 12, 01.01.2017, p. 1140-1147.

Research output: Contribution to journalArticle

Wu, Kaifeng ; Park, Young Shin ; Lim, Jaehoon ; Klimov, Victor I. / Towards zero-threshold optical gain using charged semiconductor quantum dots. In: Nature Nanotechnology. 2017 ; Vol. 12, No. 12. pp. 1140-1147.
@article{9ecfdecfadb7455baccef8d0728d7245,
title = "Towards zero-threshold optical gain using charged semiconductor quantum dots",
abstract = "Colloidal semiconductor quantum dots are attractive materials for the realization of solution-processable lasers. However, their applications as optical-gain media are complicated by a non-unity degeneracy of band-edge states, because of which multiexcitons are required to achieve the lasing regime. This increases the lasing thresholds and leads to very short optical gain lifetimes limited by nonradiative Auger recombination. Here, we show that these problems can be at least partially resolved by employing not neutral but negatively charged quantum dots. By applying photodoping to specially engineered quantum dots with impeded Auger decay, we demonstrate a considerable reduction of the optical gain threshold due to suppression of ground-state absorption by pre-existing carriers. Moreover, by injecting approximately one electron per dot on average, we achieve a more than twofold reduction in the amplified spontaneous emission threshold, bringing it to the sub-single-exciton level. These measurements indicate the feasibility of 'zero-threshold' gain achievable by completely blocking the band-edge state with two electrons.",
author = "Kaifeng Wu and Park, {Young Shin} and Jaehoon Lim and Klimov, {Victor I}",
year = "2017",
month = "1",
day = "1",
doi = "10.1038/NNANO.2017.189",
language = "English",
volume = "12",
pages = "1140--1147",
journal = "Nature Nanotechnology",
issn = "1748-3387",
publisher = "Nature Publishing Group",
number = "12",

}

TY - JOUR

T1 - Towards zero-threshold optical gain using charged semiconductor quantum dots

AU - Wu, Kaifeng

AU - Park, Young Shin

AU - Lim, Jaehoon

AU - Klimov, Victor I

PY - 2017/1/1

Y1 - 2017/1/1

N2 - Colloidal semiconductor quantum dots are attractive materials for the realization of solution-processable lasers. However, their applications as optical-gain media are complicated by a non-unity degeneracy of band-edge states, because of which multiexcitons are required to achieve the lasing regime. This increases the lasing thresholds and leads to very short optical gain lifetimes limited by nonradiative Auger recombination. Here, we show that these problems can be at least partially resolved by employing not neutral but negatively charged quantum dots. By applying photodoping to specially engineered quantum dots with impeded Auger decay, we demonstrate a considerable reduction of the optical gain threshold due to suppression of ground-state absorption by pre-existing carriers. Moreover, by injecting approximately one electron per dot on average, we achieve a more than twofold reduction in the amplified spontaneous emission threshold, bringing it to the sub-single-exciton level. These measurements indicate the feasibility of 'zero-threshold' gain achievable by completely blocking the band-edge state with two electrons.

AB - Colloidal semiconductor quantum dots are attractive materials for the realization of solution-processable lasers. However, their applications as optical-gain media are complicated by a non-unity degeneracy of band-edge states, because of which multiexcitons are required to achieve the lasing regime. This increases the lasing thresholds and leads to very short optical gain lifetimes limited by nonradiative Auger recombination. Here, we show that these problems can be at least partially resolved by employing not neutral but negatively charged quantum dots. By applying photodoping to specially engineered quantum dots with impeded Auger decay, we demonstrate a considerable reduction of the optical gain threshold due to suppression of ground-state absorption by pre-existing carriers. Moreover, by injecting approximately one electron per dot on average, we achieve a more than twofold reduction in the amplified spontaneous emission threshold, bringing it to the sub-single-exciton level. These measurements indicate the feasibility of 'zero-threshold' gain achievable by completely blocking the band-edge state with two electrons.

UR - http://www.scopus.com/inward/record.url?scp=85045150987&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85045150987&partnerID=8YFLogxK

U2 - 10.1038/NNANO.2017.189

DO - 10.1038/NNANO.2017.189

M3 - Article

C2 - 29035399

AN - SCOPUS:85045150987

VL - 12

SP - 1140

EP - 1147

JO - Nature Nanotechnology

JF - Nature Nanotechnology

SN - 1748-3387

IS - 12

ER -