Development of On-Chip Full Bridge Rectifier for the Wireless Powering of Quantum Cascade Lasers

Abstract

Since their demonstration in 1994, quantum cascade lasers, because of their reliability in emitting mid-infrared light, have seen rapid application and development in a variety of fields, such as medicine, defense, and other industry. However, an obstacle that has hindered their utility is their uniquely high threshold voltage. Because of this high voltage requirement, QCLs have been constrained to wired power, preventing them from being wirelessly powered and limiting their scope of application as a result. To solve this, efforts are being made toward the inductive wireless powering of QCLs and their applicability to industry. This thesis contributes to this effort by designing diodes made from mesas made of QC material, with the ultimate goal of using them to create an on-chip full-bridge rectifier used in the inductive WPT system for the QCL. Schottky diodes were made by depositing Ti/Au on the top of the low-doped cladding region of the QCL, and ohmic contacts were made by depositing Ge/Au/Ni/Au on exposed active region surrounding the mesa. Trenches were also etched in the material to prevent unwanted current flow, and the QCL’s intrinsically high threshold voltage prevented unwanted current flow through the active region. Testing showed that the contacts and the insulation trench functioned as expected and, with necessary improvements in fabrication, are a good candidate for use in an on-chip full bridge rectifier in the future. A potential mask layout design for the full bridge rectifier is also provided.