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Increased carrier mobility and lifetime in CdSe quantum dot thin films through surface trap passivation and doping
Daniel B Straus, E D Goodwin, E Ashley Gaulding
1National Institute of Standards and Technology , Gaithersburg, Maryland 20899-1070, United States.
The Journal of Physical Chemistry Letters
|November 5, 2015
Summary
Introducing indium into cadmium selenide (CdSe) quantum dot (QD) films enhances carrier mobility and lifetime. This improvement is crucial for advancing QD-based electronic and optoelectronic devices.
Area of Science:
- Materials Science
- Nanotechnology
- Solid State Physics
Background:
- Controlling carrier concentration and mobility in quantum dot (QD) thin films is essential for device performance.
- Surface defects in QDs can hinder charge transport and limit device applications.
Purpose of the Study:
- To investigate the impact of indium incorporation on the electrical properties of CdSe QD thin films.
- To understand how indium affects carrier mobility and lifetime in these films.
Main Methods:
- Fabrication of CdSe QD thin films with varying indium film thicknesses.
- Annealing QD films to promote indium diffusion.
- Characterization using field-effect transistor (FET) and time-resolved microwave conductivity (TRMC) measurements.
Main Results:
- Increased indium content led to higher dark and photogenerated carrier mobilities.
- Indium incorporation significantly extended carrier lifetimes.
- Observed improvements correlate with indium's ability to passivate trap states and dope the CdSe film.
Conclusions:
- Indium is an effective element for passivating surface defects and enhancing carrier transport in CdSe QD films.
- Indium doping shifts the Fermi level, improving conductivity and device potential.
- This work provides a pathway for optimizing CdSe QDs for electronic and optoelectronic applications.
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