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 language | English |
|---|---|
| Pages (from-to) | 1140-1147 |
| Number of pages | 8 |
| Journal | Nature Nanotechnology |
| Volume | 12 |
| Issue number | 12 |
| DOIs | |
| Publication status | Published - Jan 1 2017 |
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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 journal › Article
}
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.
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U2 - 10.1038/NNANO.2017.189
DO - 10.1038/NNANO.2017.189
M3 - Article
VL - 12
SP - 1140
EP - 1147
JO - Nature Nanotechnology
JF - Nature Nanotechnology
SN - 1748-3387
IS - 12
ER -