|Plasma Wave Electronics THz Detectors |
Institute for Advanced Materials and Devices
|Dmitry B. Veksler|
Adviser: Prof. M. S. Shur, Department of Physics, Rensselaer Polytechnic Institute
11:30 AM, CCR Room 201
Abstract: Although applications of terahertz (THz) radiation may span virtually all fields of science, the terahertz range of frequencies is often referred to as the “terahertz gap”, due to the lack of mature technology base. The novel class of semiconductor THz detectors based on non-linear excitations of plasma waves in a 2D electron gas is promising to cover the famous gap from the side of electronic devices. Channel with 2D electron gas acts as a resonant "cavity" for the plasma waves, excited by the incident THz radiation, and non-linearity of these waves causes rectification of radiation induced currents.
The presentation reports on theoretical and experimental study of submicron field-effect transistors (FETs) and heterodimensional Schottky diodes as plasma wave electronics THz detectors. Responsivity, sensitivity and response time of the detectors based on GaAs, GaN and Si FETs are discussed. It is demonstrated that FETs can effectively detect THz radiation with reasonable sensitivity comparable with sensitivity of commercially available THz detectors and offer fast temporal response.
The presentation covers the device performance dependences on biasing conditions in both resonant and non-resonant (broadband) detection regimes. It is shown that the DC electric current in the channel sharply increases the device responsivity and narrows the resonant detection peak, thus promising that plasma wave transistors can operate as selective and tunable detectors of electromagnetic radiation at up to room temperature or even higher.
The spatial pattern of the response of bare surface submicron field-effect transistor to THz radiation is studied in details. Analysis of the responsivity pattern dependence on drain and gate biases reveals complex nature of the transistor response, and coupling of incident radiation beam with the channel plasma.
These novel THz detectors might find applications in fast, multicolor THz cameras for spectrum analysis, detection, and imaging and will enable numerous applications in radio astronomy, biomedical imaging, homeland security, and explosive detection.
Host: Vitaly Podzorov