A high photoexcited carrier multiplication photodetector operating at room temperature is reported. The device is a GaAs n-in photodetector with double-barrier AlAs in which a thin quantum well contains a mixture of quantum dot (QD) structures. This special structure makes the proposed photoelectric detector have high sensitivity to light under an operating temperature of 300 k. Its current responsivity can reach about 7 × 10 11 A/W with 0.01 picowatts 633 nm light power and −0.5 V bias. The response voltage is 7 mV at an integration time of 80 μs. The voltage responsivity reached about 2.7 × 10 9 V/W. An embedded micro-spectrometer based on the high-sensitivity features of the photodetector has also been designed. By means of QD fluorescent sample testing and comparison, the proposed spectrometer is found to have higher sensitivity and a shorter integration time than the 'NOVA' spectrometer (product model of the spectrometer of ideaoptics, China) based on a backside-illuminated CCD (Hamamatsu, S7031-1006S). The QD spectrometer was mounded in a hyperspectral microscopy imaging system with an optical path switcher. The system has been used to analyse and to make a comparative study of the biological section. This kind of spectrometer with highly sensitive linear QD detectors has good application prospects in the fields of biological science, medical diagnosis and environmental detection.

The weak-light characteristics of the GaAs/InGaAs quantum effect photoelectric sensor are presented. In order to explore its higher sensitive application because of higher quantum efficiency, a readout integrated circuit (ROIC) of the capacitor feedback transimpendance amplifier (CTIA) was designed to deal with voltage response of novel sensor. The readout circuit integration was designed to match 2×8 the photoelectric sensor array. A 633nm laser beam shot to the window of sensor with radiation intensity 2nW the readout response voltage was 225mV and 4.5E +07V /W responsivity at 120K and 44.8μs integration time when biased voltage up to -3V. Even under 0.5nw shooting,we still can see the high sensitivity.