Design, fabrication and characterization of terahertz quantum-well photodetectors

Abstract

Terahertz (THz) photodetectors are important in the fully exploration and development of electromagnetic spectrum. However, a fast and sensitive THz photodetector ready for array integration is not available. A THz Quantum-well Photodetector (QWP) has the properties of being fast, sensitive, low-noise, and narrow-band. It is promising for large-array integration for THz imaging. In addition, a THz QWP-LED (Light-Emitting Diode) can upconvert the THz to NIR radiation and useful for THz imaging in Focal-Plane Array (FPA). In this thesis project, the theory of the intersubband transition and carrier transport in a THz QWP is studied. The designe, fabrication, measurement-system buildup, and characterization are performed. In addition, the design and fabrication process of THz QWP-LED are also carried out. Such devices have potential applications in many fields such as biology, medication and security.