Terahertz Semiconductor Quantum Well Photodetectors

Publisher Summary This chapter discusses the principle, simulation and design method, and device performance of terahertz semiconductor quantum well photodetectors (THz QWPs). Currently, various incoherent detection methods, such as bolometer, and several coherent detection methods, such as terahertz time-domain spectroscopy (THz TDS), are well developed and are used in spectroscopy and imaging fields. Because of easy production of high quality and large area uniform THz QWP materials, THz QWPs have great advantages in high sensitivity and high resolution detection, especially in the construction of focal plane arrays. THz QWPs are also useful in the detection of toxic materials and THz wireless communication. Because the characteristic absorption lines of most molecules are in THz range, under a normal continuous light source (such as high-voltage mercury lamp), the monitoring of toxic materials can be achieved by THz QWPs because of their high spectrum resolution and high response speed. The monitoring ability can be improved by multicolor THz QWPs, and multiple identifications at the same time can also be achieved. Moreover, the development of high-performance, single-element detectors and focal plane arrays will enable the THz communication and THz detection applications.