These have an average noise equivalent photon sensitivity of about 20 photons at a camera frame rate of ∼500 frames per second, which is better than the best existing infrared cameras with a similar cutoff wavelength and frame rate. Characterization of a large number of pixels shows that 1 μm devices have significantly higher sensitivity than 2 μm devices. The array is made of two groups of pixels: 50% are devices with a 1 μm base diameter and the other 50% with a 2 μm base diameter. We have fabricated a 320 × 256 array of InGaAs/InP infrared phototransistors integrated with a conventional silicon readout circuit. Here, we show the experimental validation of this prediction for III–V heterojunction phototransistors. Recent theoretical predictions suggested that reducing the internal capacitance of detectors with internal gain can increase their sensitivity. This limitation can be addressed by the internal gain of the sensors, but only if fast response time and low dark current are achieved simultaneously. The sensitivity of conventional short-wave infrared cameras is limited by their readout noise level. ![]() ![]() Ultra-sensitive and fast infrared imaging has become increasingly important in applications that require high frame rates at low light levels, such as exoplanet imaging.
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