Novel voltage-tunable far-infrared and terahertz detector based on a quantum ballistic channel

Abstract

We explore the possibility of far-infrared and terahee photovoltaic detection based on a quantum ballistic channel with an abrupt narrow end. By calculating the photoinduced intersubband transition in the channel and the transfer op!i~ized Snlit-nate ' " I ?-.structure with maximum electron transfer efficiency. The detector responsivity, operating temperature for background-limited performance and noise equivalent power are evaluated. These detectors may be used in applications such a s spectroscopy, infrared astronomy and space and environmental sensing.efficieficy of e!e&on+ oyer !he narrow end, we propose introductionEfficient far-infrared (FIR) and terahertz (THz) photon radiation in this wavelength (30-300 pm) and frequency (1-10 THz) region include bolometers, Schottky diodes and superconductor-insulator-superconductor (SIS) diodes. Bolometem are suited for some laboratory uses but are too slow in their response time fnr many app!icarinns. 2 1 s highest frequency of Schottky and SIS diodes is limited by their capacitances. It is difficult to fabricate these devices with sufficiently small capacitances for multi-THz applications. There is also a tunable detector based on the quantum Hall effect [l] in a two-dimensional electron gas (ZDEG), which requires a strong magnetic field. Recently, several authors investigated the possibility of FIR and

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“…A number of mechanisms have been tried for tunable Terahertz (THz) and far infrared (FIR) detection. [3][4][5][6][7][8][9][10] THz-FIR radiation can excite plasmonic modes and, hence, tunability of THz-FIR detection can be achieved by dynamic tuning of the energy of the plasmonic modes. FETs act as THz detectors in which energy of the plasmonic modes can be controlled by controlling the density of electrons in the 2DEG channel by application of voltage on the gate.…”

“…4,5 Another approach that leads to tunable detection of THz-FIR radiation utilizes quantum ballistic channel devices with split gates. 8,9 Split gates generate a potential well in the channel region, creating quantized energy states. The width of the channel and, hence, the width of the potential well is reduced sharply at one end of the channel to create a potential barrier for conduction of carriers in the quantized states.…”