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Surface-Reconstructed InAs Colloidal Nanorod Quantum Dots for Efficient Deep-Shortwave Infrared Emission and
Tariq Sheikh1, Wasim J Mir1, Abdulilah Alofi1
1Center for Renewable Energy and Storage Technologies (CREST), Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia.
Journal of the American Chemical Society
|October 9, 2024
Summary
Researchers developed new indium arsenide/zinc selenide core/shell colloidal nanorod quantum dots for shortwave infrared (SWIR) applications. These novel quantum dots offer tunable emission and high efficiency, overcoming limitations of traditional SWIR materials.
Area of Science:
- Materials Science
- Nanotechnology
- Optoelectronics
Background:
- Shortwave infrared (SWIR) devices are essential but conventionally use expensive, hard-to-integrate semiconductors like InGaAs.
- Colloidal quantum dots (CQDs) offer a low-cost, solution-processable alternative, but heavy-metal compositions (PbS, HgTe) are prevalent.
- Indium arsenide (InAs) CQDs are promising for SWIR, yet achieving SWIR bandgaps and managing surface traps in large InAs CQDs is challenging.
Purpose of the Study:
- To develop novel, heavy-metal-free SWIR-active colloidal quantum dots.
- To overcome synthesis challenges and surface trap issues in InAs CQDs for SWIR applications.
- To demonstrate the performance of these new CQDs in a photodetector device.
Main Methods:
- A two-step synthesis method was employed to create surface-passivated InAs/ZnSe core/shell colloidal nanorod quantum dots (CNQDs).
- The optical properties of the synthesized CNQDs were characterized, focusing on emission tunability and photoluminescence quantum yield (PLQY).
- An SWIR photodetector device was fabricated using the synthesized InAs/ZnSe CNQDs to evaluate device performance metrics.
Main Results:
- The synthesized InAs/ZnSe CNQDs exhibit high emissivity and tunable emission across the 1200-1800 nm SWIR range.
- Photoluminescence quantum yields reached up to 60%, indicating efficient light emission.
- The fabricated photodetector achieved a record external quantum efficiency of approximately 15% at 1450 nm and a low dark current of ~10⁻² mA/cm².
Conclusions:
- Surface-passivated InAs/ZnSe CNQDs provide a viable, heavy-metal-free alternative for SWIR applications.
- These novel nanostructures overcome previous limitations in InAs CQD synthesis and performance for SWIR detection.
- The demonstrated photodetector performance highlights the potential of these materials for next-generation SWIR optoelectronics integrated with CMOS technology.
