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All-electronic Switch Exceeding 10 THz



OBJECTIVE: Develop a robust, solid-state, scalable all-electronic switching and broadband amplification technology that operates in the >10 THz regime at 10+6 A/cm2 current densities with a 1W output power. 

DESCRIPTION: An electronic technology platform for the broadband amplification of currents at speeds up to 30 THz with ideally symmetric on-off characteristics and sufficient power of 1 W is needed. High frequency, high power amplifiers are currently bottlenecks for many technologies including satellite communications, remote sensing and threat detection, or electronic warfare [1], but especially for radar such as on combat aircraft [2]and ultra-high frequency telecommunications with extreme bandwidth in the atmospheric attenuation window [3, 4] around 30 THz. For such applications, additional requirements for this technology include stability over a very wide operating temperature range. This topic calls for new solid-state device architectures based on new materials because of the limitations of existing technologies. All practical broadband amplifiers that operate at >1 THz are based on the more than one-hundred year old principle of vacuum tubes. However, pushing vacuum electronics significantly above THz frequencies requires significant advances in nearly all aspects, including novel ultra-high precision manufacturing, designs for ultra-high current density electron beams, new cathode materials, novel circuit designs and optics [1]. This complexity makes solid-state devices highly desirable. However, solid-state devices based on semiconductor materials are fundamentally limited in speed by the capacitance of the depletion layers inherent in all junction-based devices. The depletion layers in diodes and transistors form capacitors and the required capacitor charging and especially discharging (“off-switching”) during transistor switching limits the maximum operating frequency. Metal-insulator-metal junctions also have inherent capacitances. Besides, demonstrated power output is in the W – few-mW range, and unpractical cryogenic cooling is typically required. Spin-based transistors have been previously pursued but their operating speeds are limited by the ferromagnetic resonance frequency [5]. The theoretical scaling relation Power 1/(frequency)2 [6] limits all technologies except for vacuum electronics to lower power than the 100 mW to 1 W needed for useful telecommunication [1]. Because of these reasons, a solid-state based broadband amplification technology is solicited with key performance parameters of 30 THz, frequency, power output of at least 1 W, and operating temperatures over a wide range, significantly above room temperature. 

PHASE I: Develop a conceptual design of a broadband, all solid-state gain-achieving device working up to 30 THz, with at least 1 W output power, and current densities of 106 A/cm2. The development will be based on an analysis of existing materials, identify the high-risk technical elements, and initial risk reduction via testing or modeling. Demonstrate the feasibility of this fundamental approach. Narrow achievable device parameters in terms of gain frequency and power response. 

PHASE II: Demonstrate gain in a real device. Demonstrate fanout. Build one prototype device that can achieve the specifications. Establish the device geometries and material properties that are most critical to achieve a large current gain and the frequency response. Optimize materials to maximize gain at frequencies > 10 THz. 

PHASE III: Commercialize electronics switching platform. Expand the capability to meet requirements for other Air Force test facilities and mature the technology for commercialization to all DoD facilities and the private sector. 


1: S.S. Dhillon, M.S. Vitiello, E.H. Linfield, A.G. Davies, C.H. Matthias, B. John, P. Claudio, M. Gensch, P. Weightman, G.P. Williams, E. Castro-Camus, D.R.S. Cumming, F. Simoens, I. Escorcia-Carranza, J. Grant, L. Stepan, K.-G. Makoto, K. Kuniaki, K. Martin, A.S. Charles, L.C. Tyler, H. Rupert, A.G. Markelz, Z.D. Taylor, P.W. Vincent, J.A. Zeitler, S. Juraj, M.K. Timothy, B. Ellison, S. Rea, P. Goldsmith, B.C. Ken, A. Roger, D. Pardo, P.G. Huggard, V. Krozer, S. Haymen, F. Martyn, R. Cyril, S. Alwyn, S. Andreas, N. Mira, R. Nick, C. Roland, E.C. John, B.J. Michael, The 2017 terahertz science and technology roadmap, Journal of Physics D: Applied Physics 50(4) (2017) 043001.

2:  T. Withington, Chinese Claims of Terahertz Radar?, 2018 (accessed 12/18/2018.2018).

3:  G.J. Zissis, W.L. Wolfe, The infrared handbook, Infrared Information and Analysis (IRIA) Center for the Office of Naval Research, Washington, 1978.

4:  S. Hakusui, Fixed Wireless Communications at 60GHz Unique Oxygen Absorption Properties. 2001 (accessed 12/18/2018.2018). [5] M. Johnson, Bipolar spin switch, Science 260(5106) (1993) 320-3. [6] J.H. Booske, Plasma physics and related challenges of millime

KEYWORDS: THz Electronics, All-electronics Circuits 

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