Colloidal InAs Quantum Dot-Based Infrared Optoelectronics Enabled by Universal Dual-Ligand Passivation

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• Solution-processed low-bandgap semiconductors are essential for next-generation infrared (IR) detection.
• Colloidal quantum dots (CQDs), particularly III-V group materials like Indium Arsenide (InAs), offer tunable bandgaps and non-toxicity but lag behind lead-based devices in performance.

Purpose of the Study:

• To develop a universal surface-passivation method for InAs CQDs.
• To enhance the stability and performance of CQDs for near-infrared (NIR) photodetector applications.
• To demonstrate tunable photodetector gain and fast response times using solution-processed techniques.

Main Methods:

• A novel intermediate phase transfer (IPT) process was employed to exchange native ligands with aromatic ligands on the InAs CQD surface.
• IPT was used to create stable CQD inks dispersed in green solvents.
• Near-infrared (NIR) photodetectors were fabricated using solution-processed CQDs with controlled surface ligands.

Main Results:

• The IPT method yielded highly stable InAs CQD inks.
• Surface ligand control via IPT enabled modulation of surface-mediated photomultiplication, achieving gain control up to approximately 10.
• The optimized CQD photodiode exhibited fast rise/fall response times of approximately 12/36 ns.
• The photodetector achieved one of the highest figures of merit (FOM) among solution-processed non-toxic semiconductors in the NIR range.

Conclusions:

• The developed IPT method provides a universal approach for surface passivation of InAs CQDs.
• This technique significantly enhances the performance of solution-processed non-toxic NIR photodetectors.
• The findings pave the way for advanced IR detection technologies in areas like autonomous driving and quantum communications.