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GaAsBi/GaAs multi-quantum well LED grown by molecular beam epitaxy using a two-substrate-temperature technique
Pallavi Kisan Patil1, Esperanza Luna2, Teruyoshi Matsuda1
1Graduate School of Science and Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama, Ehime, Japan.
Nanotechnology
|February 2, 2017
Summary
A novel two-substrate-temperature technique significantly reduces bismuth segregation in gallium arsenide/gallium arsenide-bismuth multiple quantum wells, enhancing material quality for 1.23 μm light-emitting diodes.
Area of Science:
- Materials Science
- Semiconductor Physics
- Optoelectronics
Background:
- Gallium arsenide-bismuth (GaAsBi) alloys are promising for optoelectronic devices, but bismuth segregation during growth degrades material quality.
- Previous methods for growing GaAsBi/GaAs multiple quantum wells (MQWs) have struggled with significant bismuth surface segregation, limiting device performance.
- Optimizing growth conditions is crucial for high-quality dilute bismide heterostructures.
Purpose of the Study:
- To develop and evaluate a two-substrate-temperature (TST) technique for growing high-quality GaAsBi/GaAs MQWs.
- To investigate the impact of TST on bismuth segregation and material microstructure.
- To demonstrate the effectiveness of TST-grown MQWs in light-emitting diode (LED) applications.
Main Methods:
- Molecular beam epitaxy (MBE) growth of GaAsBi/GaAs MQWs using a TST approach, with different temperatures for quantum wells (QWs) and barriers.
- Transmission electron microscopy (TEM) for microstructural analysis and local determination of bismuth distribution.
- Fabrication and characterization of LEDs, including current-voltage (I-V) measurements, photoluminescence (PL), and electroluminescence (EL).
Main Results:
- TEM confirmed homogeneous MQWs free of extended defects and uniform bismuth distribution.
- The TST technique significantly reduced bismuth segregation by up to 18% compared to previous reports.
- Room-temperature electroluminescence at 1.23 μm was achieved with TST-grown MQWs, demonstrating improved optical properties.
Conclusions:
- The TST technique is highly effective in minimizing bismuth segregation in GaAsBi/GaAs MQWs, leading to superior material and interface quality.
- TST-grown MQWs enable the fabrication of high-performance LEDs operating at 1.23 μm.
- This growth strategy highlights the potential of TST for future dilute bismide-based heterostructure devices.
