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Model To Determine a Distinct Rate Constant for Carrier Multiplication from Experiments.
Frank C M Spoor1, Gianluca Grimaldi1, Sachin Kinge2
1Optoelectronic Materials Section, Department of Chemical Engineering, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands.
ACS Applied Energy Materials
|February 5, 2019
Summary
We present a new method to experimentally determine the carrier multiplication (CM) rate constant, a key factor in semiconductor efficiency. This breakthrough allows for direct measurement, advancing the understanding of CM in materials like PbSe quantum dots.
Area of Science:
- Semiconductor physics
- Quantum dot optoelectronics
- Materials science
Background:
- Carrier multiplication (CM) is crucial for enhancing semiconductor efficiency, where one photon generates multiple electron-hole pairs.
- CM efficiency depends on the competition between carrier generation and cooling via phonon emission.
- Previously, CM rates were only accessible through theoretical calculations.
Purpose of the Study:
- To develop and demonstrate an experimental method for determining the carrier multiplication (CM) rate constant.
- To validate the method using PbSe quantum dots.
- To offer a simplified estimation technique for CM rate constants when detailed experimental data is unavailable.
Main Methods:
- Extracting the CM rate constant from experimental data of hot charge carrier relaxation times and CM yields.
- Applying the developed method to PbSe quantum dots.
- Proposing a simplified approach using estimated energy loss rates for CM rate constant estimation.
Main Results:
- Successfully extracted a distinct CM rate constant from experimental data for the first time.
- Demonstrated the method's applicability to PbSe quantum dots.
- Provided a simplified method to estimate CM rate constants above the CM onset.
Conclusions:
- The developed experimental method enables direct measurement of CM rate constants, overcoming previous theoretical limitations.
- This work provides a pathway for more accurate characterization of CM in quantum dots and other semiconductor materials.
- The simplified estimation method offers a practical tool for assessing CM efficiency even with limited experimental data.
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