High-gain photoelectric detector

Abstract

The invention discloses a high-gain photoelectric detector which comprises an emitting electrode, a base electrode, an absorption layer and a collector electrode which are sequentially arranged from bottom to top, and further comprises a periodic quantum structure layer which is arranged between the emitting electrode and the collector electrode or arranged in the base electrode or arranged in the emitting electrode. The periodic quantum structure layer comprises a repeated structure of a plurality of periods, and each period contains a semiconductor heterojunction. The periodic quantum structure can block diffusion of a base electrode hole to the emitting electrode and improve the electron injection ratio of an emitter junction and the amplification factor of the transistor on one hand, and on the other hand, the periodic quantum structure can bind the hole with larger effective mass in the multilayer quantum structure to reduce the recombination loss, and enables the hole life in the device to exceed the electron transport time. Therefore, a superposed photoconductive gain is generated in the phototransistor.

Description

technical field [0001] The present invention relates to the technical field of semiconductor photodetectors, more specifically, to a high-gain photodetector. Background technique [0002] Photodetectors are widely used in optical communication, imaging, environmental monitoring, assisted driving and various experimental tests. For photodetectors, responsivity is a very important index. High-responsivity semiconductor photodetectors with internal gain can realize high-sensitivity detection of weak light signals at room temperature and low bias voltage, and can save additional The signal amplifier makes the photoelectric detection system more compact, portable, and low in cost. The n-p-n type phototransistor is a commonly used semiconductor photodetector with internal gain. The principle of photoelectric gain is that when the base region is suspended, the holes generated by light absorption in the collector junction will be under the action of the built-in field and the exter...

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Problems solved by technology

[0004] However, current phototransistors and heterojunction phototransistors still have deficiencies. For example, for weak light signals or even single photon incident conditions, the number of photogenerated holes is extremely limited, and it is difficult to have a significant impact on the height of the emitter junction barrier. Limiting phototransistors to detect extremely faint light

Other common internal gain mechanisms of detectors also have their own limitations. For example, avalanche photodetectors require a low material defect density to avoid premature breakdown, and require a high operating voltage; photoconductive detectors have relatively low dark current. High, and the uncontrollable gain process that generally involves trap states will seriously degrade the response speed of the detector. Although the device can obtain high responsivity, the response speed is generally on the order of milliseconds or even seconds, and the application range is severely limited.

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