Terahertz oscillators using electron devices - an approach with Resonant tunneling diodes

Abstract

Abstract:Resonant tunneling diodes (RTDs) have the potential for compact and coherent terahertz (THz) sources operating at room temperature. In this paper, recent results of THz oscillators with RTDs are described. A fundamental oscillation frequency up to 831 GHz was achieved with RTD having high available current density and low capacitance. By the structure reducing the transit time, the frequency further increased to 1.04 THz. This is the first achievement of a fundamental oscillation above 1 THz in room-temperature electronic single oscillators. The output power of 400 μW at 550 GHz was obtained in a single oscillator by the offset-fed slot antenna. Coherent power combining with multi-element array was observed. The spectral linewidth, frequency change with bias voltage, and direct modulation were also described.

Progress in Compact Room Temperature THz Radiation Sources

“…The RTD [69,70] is based on the confinement of electrons within a quantum well (e.g. heterobarriers (i.e.…”

Epitaxial Designs for Maximizing Efficiency in Resonant Tunneling Diode Based Terahertz Emitters

“…In order to exploit this characteristic for free-space THz wave emission, the RTD requires coupling into a waveguide and suitable antenna. The small-signal THz behavior can be predicted from the I-V characteristics using methodology for optimizing the RF topologies as discussed by Asada and Suzuki [15].…”

“…Experimentally, attempts to maximize the output power of RTD-based THz emitters through band-gap engineering of the epitaxial structure include: collector delta-doping or grading alloy content of the emitter [15], a sub-well [16], lowering conduction losses [8], in addition to modifications to the antenna element [17]. Such attempts often come with the risk of sacrificing epitaxial growth quality [18], requiring careful consideration of stress accumulation due to lattice misfit [19].…”

Photoluminescence Characterisation of High Current Density Resonant Tunnelling Diodes for Terahertz Applications

“…Recent optical THz devices include the p-type Ge laser [2], THz quantum cascade laser (QCL) [3], THz wave parametric amplifier [4], and the uni-travelling carrier photodiode (UTC-PD) [5]. On the electron device side, devices such as the tunnel injection transit time negative resistance (TUNNETT) diode [6], Gunn diode [7], high-electronmobility transistor (HEMT) [8], and resonant tunnelling diode (RTD) [9] are being studied. THz waves will provide new capabilities for applications in various fields, including ultra-broadband wireless communications [10], spectroscopic sensing and imaging [11], [12], and high-resolution radar [13].…”