The Study for the Performance of Quantum Well Photodetector with Device Noise Analyses

• Main Authors: HUANG,ZI-YU, 黃姿妤
• Other Authors: CHEN,ZI-JIANG
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/01807703902716340237

碩士 === 國防大學理工學院 === 電子工程碩士班 === 102 === When evaluating the quantum well infrared photodetector (QWIP), two critical parameters must be considered. One is the quantity of the photo current and the other is the analysis of the noise current. Accurately measuring the noises of the device enables understanding of the physical characteristics of the device. It also increases the accuracy of the infrared photodetector. The noises from the measuring system are present when measuring the noises of the device. Therefore, it is necessary to reduce external disturbances and to eliminate the noises from the measuring system. This thesis includes two major topics: the system noise analysis and the photo-electric analysis of the device. Experimental procedures to accurately measure the system noises are presented in the first part of this thesis. To accurately measure the subtle noises in the measuring system, the existing thermal noises of standard resistors are used as the calibrating tool for the measuring system. Thevenin equivalents and Norton equivalents are used to model the noise sources of the entire measuring system. Then, the superposition theorem is used to calculate the noise current in the measuring system. Common noises in the measuring system, and functions and characteristics of the measuring equipment are introduced in this part. The assembling of the measuring system and signal circuits is also introduced in detail. Finally, the semiconductor parameter analyzer (HP4156B) and the dynamic signal spectrum analyzer (35670A) are used to measure the noises in the measuring system. The second part of this thesis discusses and analyzes the optical characteristics such as the responsivity, dark current, activation energy, noise current, photo-current gain and detectivity of the long-wave-length and dual-band devices. Thermal noise measuring of the system is presented in the discussion of the noises of the device. Temperature, electric field and frequency are also considered. The results show that the theoretical noises (thermal noises, 1/f noises and g-r noises) of the device are identical to the experimental measurements.