Intermediate temperature grown GaAs/AlGaAs photodetector with low dark current and high sensitivity

Abstract

A photodetector in which Schottky metal laterally contacts the molecular beam epitaxy grown heterointerface of intermediate-temperature GaAs and Al0.24Ga0.76As is reported. The device processed on 400 °C shows very low dark current, less than 25 fA/μm2 (0.5 pA/μm), with a high dc responsivity of about 10 A/W at low optical power levels. The device is process compatible with high electron mobility transistor technology.

Resonant-cavity-enhanced heterostructure metal–semiconductor–metal photodetector

“…5 In particular, we have previously proposed AlGaAs/GaAs heterostructure metalsemiconductor-metal photodetectors ͑HMSM-PDs͒ that show much less dark current than conventional MSM due to both the two-dimensional electron gas ͑2DEG͒ and the effect of barrier enhancement due to the wide-gap material. [7][8][9] A common problem with planar, as well as vertical, photodetectors is the trade off between speed and quantum efficiency; in order to achieve a fast response from photodetectors, the depleted absorption region needs to be small for reduced path length, but this results in a decreased responsivity due to small absorption depth. Resonant cavity technique offers the possibility to balance such conflict between fast speed and sensitivity.…”

Passive Amplification Effect in Thin Pyroelectric Films

“…One of the defining parameters of detectors of radiation is current sensitivity. For pyroelectric detectors it is of 1 mA=W [6], much lower than the current sensitivity of photon detectors, 1 A=W and more [7].…”