Infrared Photodetectors: Quantum Well and Dot Technologies

This lecture discusses the design and functionality of Quantum Well Infrared Photodetectors (QWIPs) and Quantum Dot Infrared Photodetectors (QDIPs). The instructor explains the working principles of these devices, emphasizing the importance of electric field orientation for effective light absorption. The lecture covers the necessity of gratings for light deflection in QWIPs and the advantages of using silicon processors for readout in these systems. The instructor also highlights the ability to adjust the wavelength of maximum sensitivity by modifying the thickness of the quantum wells. Additionally, the lecture presents examples of responsivity and detectivity across various wavelengths, illustrating the commercial applications of these technologies. The discussion extends to thermal infrared detectors, comparing their performance with photonic infrared detectors, and concludes with a summary of the operational characteristics and applications of both types of infrared photodetectors, emphasizing their respective advantages and limitations in detecting infrared radiation.