Ultrafast control of the optical transition in type-II colloidal quantum wells
Manipulating the optical transition in semiconductors at ultrashort timescales is of both fundamental interest and central importance for emerging photonic applications. Traditionally, this manipulation is realized by electrostatic gating via Stark effects or band-gap renormalizations. Here, we repo...
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sg-ntu-dr.10356-1721082024-03-11T15:35:30Z Ultrafast control of the optical transition in type-II colloidal quantum wells Yu, Junhong Durmusoglu, Emek Goksu Wang, Yimeng Sharma, Manoj Demir, Hilmi Volkan Dang, Cuong School of Physical and Mathematical Sciences School of Electrical and Electronic Engineering LUMINOUS! Centre of Excellence for Semiconductor Lighting & Displays The Photonics Institute CNRS International NTU THALES Research Alliances Physics Colloidal Quantum Wells Type-II Heterojunction Manipulating the optical transition in semiconductors at ultrashort timescales is of both fundamental interest and central importance for emerging photonic applications. Traditionally, this manipulation is realized by electrostatic gating via Stark effects or band-gap renormalizations. Here, we report an ultrafast and all-optical route to engineer an indirect transition in core-crown colloidal quantum wells (CQWs), namely, CdSe/CdTe, with a type-II band alignment. Following the intense laser pulse excitation, the indirect band transition energy exhibits a pronounced blueshift-redshift crossover on the picosecond timescale, stemming from the formation and dissipation of the transient electric field (E-field) that forms upon photoexcitation to compensate for the driving force provided by the band offsets. Both the energy shift and dynamics of the transient E-field can be modulated optically by tuning the laser pulse excitation fluence. Our finding demonstrates a strong analogy between the type-II heterojunction and a p-n junction with respect to carrier equilibrium processes, which holds promise to facilitate the integration of CQWs within optical switching networks. Agency for Science, Technology and Research (A*STAR) Ministry of Education (MOE) Submitted/Accepted version C.D. thanks the Ministry of Education, Singapore, for the financial support under its AcRF Tier 2 grant (no. MOE- T2EP50121-0012). H.V.D. acknowledges the financial support in part from the Singapore Agency for Science, Technology and Research (A*STAR) MTC program under grant no. M21J9b0085, the Ministry of Education, Singapore, under its Academic Research Fund Tier 1 (no. MOE-RG62/20), and in part from TUBITAK nos. 119N343, 20AG001, 121N395, and 121C266. H.V.D. also acknowledges support from TUBA and TUBITAK 2247-A, National Leader Researchers Program (no. 121C266). 2023-11-24T05:03:28Z 2023-11-24T05:03:28Z 2023 Journal Article Yu, J., Durmusoglu, E. G., Wang, Y., Sharma, M., Demir, H. V. & Dang, C. (2023). Ultrafast control of the optical transition in type-II colloidal quantum wells. ACS Photonics, 10(5), 1250-1258. https://dx.doi.org/10.1021/acsphotonics.2c01799 2330-4022 https://hdl.handle.net/10356/172108 10.1021/acsphotonics.2c01799 2-s2.0-85154018433 5 10 1250 1258 en MOE- T2EP50121-0012 MOE-RG62/20 M21J9b0085 ACS Photonics © 2023 American Chemical Society. All rights reserved. This article may be downloaded for personal use only. Any other use requires prior permission of the copyright holder. The Version of Record is available online at http://doi.org/10.1021/acsphotonics.2c01799. application/pdf |
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Physics Colloidal Quantum Wells Type-II Heterojunction Yu, Junhong Durmusoglu, Emek Goksu Wang, Yimeng Sharma, Manoj Demir, Hilmi Volkan Dang, Cuong Ultrafast control of the optical transition in type-II colloidal quantum wells |
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Manipulating the optical transition in semiconductors at ultrashort timescales is of both fundamental interest and central importance for emerging photonic applications. Traditionally, this manipulation is realized by electrostatic gating via Stark effects or band-gap renormalizations. Here, we report an ultrafast and all-optical route to engineer an indirect transition in core-crown colloidal quantum wells (CQWs), namely, CdSe/CdTe, with a type-II band alignment. Following the intense laser pulse excitation, the indirect band transition energy exhibits a pronounced blueshift-redshift crossover on the picosecond timescale, stemming from the formation and dissipation of the transient electric field (E-field) that forms upon photoexcitation to compensate for the driving force provided by the band offsets. Both the energy shift and dynamics of the transient E-field can be modulated optically by tuning the laser pulse excitation fluence. Our finding demonstrates a strong analogy between the type-II heterojunction and a p-n junction with respect to carrier equilibrium processes, which holds promise to facilitate the integration of CQWs within optical switching networks. |
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School of Physical and Mathematical Sciences |
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School of Physical and Mathematical Sciences Yu, Junhong Durmusoglu, Emek Goksu Wang, Yimeng Sharma, Manoj Demir, Hilmi Volkan Dang, Cuong |
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Article |
author |
Yu, Junhong Durmusoglu, Emek Goksu Wang, Yimeng Sharma, Manoj Demir, Hilmi Volkan Dang, Cuong |
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Yu, Junhong |
title |
Ultrafast control of the optical transition in type-II colloidal quantum wells |
title_short |
Ultrafast control of the optical transition in type-II colloidal quantum wells |
title_full |
Ultrafast control of the optical transition in type-II colloidal quantum wells |
title_fullStr |
Ultrafast control of the optical transition in type-II colloidal quantum wells |
title_full_unstemmed |
Ultrafast control of the optical transition in type-II colloidal quantum wells |
title_sort |
ultrafast control of the optical transition in type-ii colloidal quantum wells |
publishDate |
2023 |
url |
https://hdl.handle.net/10356/172108 |
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1794549354123493376 |