Quantum dots photodetector and micro-area spectra application

Abstract

ABSTRACTIn this paper, the authors mainly studies on optical and electrical characteristics of 64 pixels quantum dots photodetector, and explore the application of micro-spectrometer as well. The photodetector has AlAs double barrier structures with a layer self-assembled InAs quantum dots and In0.15Ga0.85 As quantum well. The capture of photo-excited carriers on InAs quantum dots and In0.15Ga0.85As quantum well enable local modulation of the electrostatic potential, which help increase the photodetector sensitivity. The photocurrent responsivity is about 5.69E7 A/W with 0.01 picowatts power He-Ne laser illumination and -3 V bias voltage at liquid nitrogen temperature, wherein the internal gain of the photodetector is even higher than 1.11E8. We have designed readout circuits and an android-based micro-spectrometer based on quantum dots photodetector. In order to study micro-area spectra of biological samples, the mico-spectrometer has been mounted in a microscopy hyperspectral imaging system with C-Mount optical path switcher. The experimental results show that the red blood cell transmittance spectra obtained by the two spectral measurement systems are well coincided, and the sensitivity of quantum dot micro-spectrometer is much higher than the commercial CCD spectrometer.