All-Inorganic, Bicontinuous, Bandgap-Engineered Epitaxially-Fused PbSe Quantum Dot/CdS Matrix Heterostructures for...

Area of Science:

• Materials Science
• Nanotechnology
• Semiconductor Physics

Background:

• Epitaxially fused lead selenide quantum dot (PbSe QD) assemblies exhibit promising infrared absorption properties.
• Achieving stable, high-performance optoelectronic devices requires robust semiconductor heterostructures with tailored electronic properties.

Purpose of the Study:

• To create all-inorganic, bicontinuous, bandgap-engineered PbSe QD/CdS matrix heterostructures.
• To enhance the stability and performance of PbSe QD-based infrared optoelectronic devices.

Main Methods:

• Utilized postdeposition sequential colloidal atomic layer deposition (c-ALD) to grow a CdS matrix on PbSe QDs.
• Controlled CdS growth and annealing to engineer stoichiometry, carrier type, concentration, and mobility.
• Fabricated and characterized field-effect transistors and infrared photoconductors.

Main Results:

• Achieved epitaxially fused PbSe QD/CdS matrix heterostructures with a bicontinuous architecture.
• Maintained low-energy excitonic absorbance of PbSe QDs while increasing absorbance above the CdS bandgap.
• Enhanced oxidative and thermal stability, preserving heterostructures after annealing at 150 °C.
• Demonstrated modulated carrier properties and improved photocurrent modulation and infrared photoresponsivity in photoconductors.

Conclusions:

• The developed bicontinuous heterostructures offer an architecture for high-mobility charge transport and long carrier lifetimes.
• These materials are promising for high-speed, high-quantum-efficiency electronic and optoelectronic devices.
• Bandgap engineering and stability improvements pave the way for advanced infrared detector applications.