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Planar, Al0.3Ga0.7As-passivated-base, heterojunction bipolar phototransistors.
G W Anderson1, F J Kub, T F Carruthers
1Naval Research Laboratory, Washington, DC 20375-5347, USA.
Applied Optics
|February 1, 1997
Summary
New planar Gallium Arsenide (GaAs) heterojunction bipolar phototransistors were developed. These devices show promise for high-speed optical processing applications requiring a 100-MHz bandwidth.
Area of Science:
- Optoelectronics
- Semiconductor Devices
- Materials Science
Background:
- Heterojunction bipolar phototransistors (HBPs) are crucial for optoelectronic applications.
- Advancements in materials and device design are needed to improve performance and speed.
Purpose of the Study:
- To design and demonstrate novel planar Gallium Arsenide (GaAs) heterojunction bipolar phototransistors.
- To evaluate the performance characteristics of these new phototransistors for optical processing.
Main Methods:
- Utilized a GaAs/Al(0.3)Ga(0.7)As molecular-beam-epitaxy materials system.
- Incorporated an Al(0.3)Ga(0.7)As passivated, 10-nm-thick base, a depleted high-low emitter, and low emitter-base capacitance.
- Fabricated devices with specific electrical contact configurations for emitter and collector.
Main Results:
- Achieved rise times between 747-891 ps under impulse optical excitation at 810 nm.
- Measured photocurrent gains ranging from 0.67 to 19 at 810 and 850 nm, varying with experimental conditions.
- Demonstrated device functionality suitable for specific optical processing tasks.
Conclusions:
- The designed planar GaAs heterojunction bipolar phototransistors exhibit promising performance.
- These devices are suitable for heterodyne photodetector arrays in coherent optical processing channelizers.
- Potential for applications requiring a 100-MHz bandwidth and high-speed optical detection.
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