Photoelectricity Of Subthreshold MOSFETs And Design Of Application System

As a kind of important semiconductor device, the function of photoelectric detector is transferring optical signal to electric signal. Through this way, measure, transmit and storage of optical signal can be implemented by electric method, while it can be widely used on the areas of detect, monitor and communication. Nowadays, with the development of information industry, more and more optic-electric application systems are designed and fabricated, and as the key of whole system, photoelectric detectors are researched persistently. For the traditional photoelectric detectors, only DC electric signal can be gotten when the input illumination is constant. Added circuits are needed to transfer this DC electric signal to AC electric signal for the succeeding treatment. In this way, the electric circuits are complex and not easy to integrate, moreover, with the increase of electric devices, the performances of systems, such as noise, stability and power, will degenerate. So, to solve this question, a novel photoelectric detector is introduced in this thesis. It can output AC electric signal directly when the input illumination is constant. Using it, two optic-electric application systems are designed, while the one is about low illumination detection and the other is an optical fiber colorimetric thermometer.Firstly, the theories of photoelectric detector and MOSFET are introduced as the base of our novel photoelectric detector-internal modulated MOSFET photoelectric detector. Above that, the concept of internal modulation and the structure of internal modulated MOSFET photoelectric detector are pointed out. The parameters, work condition, performance of the novel photoelectric detector are also discussed. This part introduces the key concept about the whole thesis.Secondly, the internal modulated MOSFET photoelectric detector is fabricated and of course is tested. The test results show that our novel device is a good photoelectric detector, while under the constant illumination, it can output DC electric signal. This part verifies our theory of internal modulation.After above theory and experiment description about our photoelectric detector, two optic-electric application systems based on the internal modulated MOSFET photoelectric detector are given. Our device is sensitive to the intensity of input light, so we develop a low illuminance detection system. This system can detect the illuminance about 10-6 Lx, and can be widely used on spectral analysis, fluorescence detection and chemi-luminescence detection. The other application system is an optical fiber colorimetric thermometer. Using our device’s high sensitivity on infrared band, it compares the detections about different wavelength and calculates the temperature. It employs optical fiber as input interface, and can be widely used on areas that need non-contact temperature measurement. These two optic-electric application systems have been implemented and applied.Finally, the above studies about our device’s theory, test and application are summarized. Moreover, the idea of future work is brought out in this part.