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Recombination Dynamics in Thin-film Photovoltaic Materials via Time-resolved Microwave Conductivity
Published on: March 6, 2017
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Carrier generation and recombination dynamics in type-II ZnSeTe/ZnMnSe quantum structures
1Department of Electrophysics, National Chiao Tung University, Hsinchu 30010, Taiwan.
Nanotechnology
|July 9, 2015
Summary
This study explores carrier dynamics in type-II quantum structures for photovoltaic applications. Long carrier lifetimes exceeding 120 ns were observed, increasing with temperature, beneficial for device performance.
Area of Science:
- Semiconductor Physics
- Materials Science
- Photovoltaics
Background:
- Type-II band alignment is crucial for efficient carrier transport in photovoltaic devices.
- Understanding carrier generation and recombination dynamics is key to optimizing photovoltaic performance.
Purpose of the Study:
- To investigate carrier generation and recombination dynamics in a type-II quantum structure.
- To analyze the role of isoelectronic centers and temperature on carrier lifetimes.
Main Methods:
- Fabrication of a type-II quantum structure using ZnSe0.92Te0.08 highly mismatched alloys (HMAs) and Zn0.97Mn0.03Se.
- Study of photoinduced carrier dynamics, including relaxation and recombination processes.
- Temperature-dependent measurements of carrier lifetimes.
Main Results:
- Photoinduced holes in ZnSe0.92Te0.08 HMAs relax to isoelectronic centers.
- Recombination occurs between holes and free electrons in Zn0.97Mn0.03Se.
- Long carrier lifetimes (>120 ns) were observed due to spatially indirect excitons bound to Te trapping states, increasing with temperature.
Conclusions:
- The type-II quantum structure exhibits favorable carrier dynamics for photovoltaic applications.
- Isoelectronic Te trapping states significantly enhance carrier lifetimes.
- The temperature-dependent increase in carrier lifetime suggests potential for enhanced photovoltaic device performance at elevated temperatures.
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