NSF Award
1711738
A 3-year tri-university (Ohio State, Wright State and Texas State) project is proposed to advance a new class of efficient and stable oscillator circuits based upon quantum tunneling. It will explore a class of tunnel diode based relaxation oscillators and extend this to a novel domino effect pulse amplifier design. Past stability issues of tunnel diode based oscillators are addressed by oscillating beyond the negative differential resistance region. This larger voltage swing also provides for significantly larger output powers. Effort will be made to extend their operational frequency beyond the state-of-the-art through electromagnetic modeling simulations. Their simplicity and low-power consumption could also make them a candidate for Internet-of-Things objects. Tunnel diode based electronics provides a pathway for energy thrifty "green" circuitry with concurrently high output power and with unprecedented stability. A full-time graduate student will be directly supported at both Ohio State and Wright State. The shortlist candidate graduate student for each group are both female undergraduates who began their research career as undergraduates in Berger's lab. Supplemental funding requests will be applied for to support 1-2 undergraduates additionally, along with scientific visitations, to perpetuate this legacy. This project provides tremendous benefits to society and humankind by advancing low-cost, ultra-low power consumption radio frequency sources, and stable radio frequency sources for new advances in compact clock signal generation.<br/><br/>A key aim of this project oscillator design, transmission line modeling and radio frequency measurements to develop and mature a new type of stable tunnel diode based oscillator that addresses the tunnel diode stability issues by oscillating beyond the negative differential resistance region. This larger voltage swing also provides for significantly larger output powers. Advances by this team, leveraging their first report of the experimental determination of the quantum-well lifetime influence upon the large-signal resonant tunneling diode switching time, this team now is poised to advance compact oscillator circuits with high conversion efficiencies, generating large and stable output powers. The tunnel diode based circuitry will provide (i) for the significant advancement of relaxation oscillators that address the tunnel diode stability issues which thwarted resonant tunneling diode adoption, and (ii) creation of a wholly new "domino amplifier" that daisy chains each relaxation oscillator stage to the next using progressively larger tunnel diode sizes with concurrently increasing output powers. Without the stability afforded by the relaxation oscillator design, large tunnel diode based oscillators would be too unstable, and thus prevent this novel approach. The relaxation oscillators have been studied in the past and shown to produce radio frequency output power exceeding 1 mW, as expected, but their maximum (repetition) frequency of oscillation has only been 50 GHz], well below the expectation. This will be an early topic of the proposed study where full- wave electromagnetics and nonlinear-device/circuit interactions will be simulated, especially examining the effect of planar-transmission line dispersion and short-circuit reflectance. This knowledge will then be used to demonstrate a totally new and potentially revolutionary tunnel diode switching component - the "domino" pulse amplifier. The domino amplifier has the ability to utilize inherently fast tunnel diode switching to create unilateral, large-signal gain. All of the materials for the proposed effort will be InP based. These materials have produced some of the best resonant tunneling diodes to date as measured by peak-to-valley current ratio, peak current density, maximum frequency of oscillation, and switching time. A systematic exploration and development of resonant tunneling diode technology in three vertically integrated research thrusts: (i) advanced epitaxial control and quantum-based device physics design using non-equilibrium Green's function, (ii) compact high-power resonant tunneling diode based relaxation oscillators, (iii) novel domino amplifiers, and (iv) nonlinear-device, integrated-circuit interaction and electromagnetics.
