At the 2024 CS MANTECH conference, Robert presents his work finding unique device physics in his transistor injected quantum cascade structure (TI-QCS).
Category: TI-QCL
Transistor-Injected Quantum-Cascade Laser (TI-QCL)
Ultra-sensitive current bistability and light switching in a resonant tunneling superlattice transistor
Bistability in the current–voltage characteristics of semiconductor superlattices and quantum cascade laser structures has the potential for wide-ranging applications, particularly in sensing systems. However, the interdependency of applied bias and current injection in conventional two-terminal structures has led to complications in analysis and rendered the bistability phenomenon difficult to implement in practical applications. Here, we report a new kind of electronic bistability coupled to optical switching in a resonant tunneling bipolar superlattice transistor. This bistability manifests as sharp discontinuities in the collector current with extremely small variations of the applied voltage, which arise from unstable tunneling transmission across the hetero-barrier between the two-dimensional electron gas (2DEG) at the edge of the transistor base and the collector superlattice structure. The electronic transitions between high and low quantum mechanical transmissions are demonstrated to be caused by self-consistent variations of the internal electric field at the heterointerface between the 2DEG and the superlattice. They are also present in the base current of the three-terminal device and result in sharp switching of near-infrared spontaneous light emission output from an interband radiative recombination process with a peak emission wavelength of 1.58 m. A comprehensive quantum mechanical theoretical model accounting for the self-consistent bistable tunneling transmission is in quantitative agreement with the experimental data. The measured peak transconductance sensitivity value of 6000 mS can be used in the highly sensitive detector and non-linear device applications.
Robert, Kevin, and Leah Present at the Engineering Research Fair
Robert Kaufman, Kevin Pikul, and Leah Espenhahn present a high-level view on the research conducted within the group at the 2023 Engineering Research Fair. Over the course of two hours, 74 undergraduate students show interest in the group and the research being performed.
Design and Fabrication Considerations for Transistor-Injected Quantum Cascade Lasers for Compact, Efficient, and Controllable Mid-Wave Infrared Lasing
The transistor-injected quantum cascade laser (TI-QCL) is a novel design for a mid-wave infrared (MWIR) laser that seeks to overcome some of the primary limitations of standard quantum cascade lasers (QCLs). By growing the active cascade region within the base-collector junction of an npn heterojunction bipolar transistor (HBT), independent control of the injection current and active region bias is achievable through the emitter current and base-collector reverse bias respectively. The active region bias is important to properly align the lasing states and to control the lasing wavelength. Physical design limitations of the TI-QCL and their effects on the fabrication process of samples is presented. In order to characterize device performance and validate fabrication improvements, InP-based device samples designed for λ= 7.3 µm emission are fabricated. Preliminary characterization results are shown in the form of diode measurements to validate the HBT electrical operation of the TI-QCL which is necessary to realize the optical benefits of the device.
Control of Radiative Base Recombination in the Quantum Cascade Light-Emitting Transistor using Quantum State Overlap
The Advanced Semiconductor Device and Integration Group is proud to share a recent publication by Kanuo Chen, Fu-Chen (Alex) Hsiao, Brittany Joy, and Professor Dallesasse on demonstrating the ability to control radiative base recombination in a quantum-cascade light emitting transistor that shows performance benefits of a transistor-injected QCL over conventional QCL devices.