Bias-free selectively doped AlxGa1-x As-GaAs picosecond photodetectors

Abstract

We demonstrate a novel AlxGa1-x As-GaAs picosecond photodetector which does not require any bias voltage. High-speed operation is achieved by an inherent capacitive coupling, a unique microwave mounting scheme, and a selectively doped structure. An observed rise time of 30 ps and a full width at half-maximum of 60 ps have been reproducibly obtained for a device with an area two orders of magnitude larger than a previously reported device. This detector enables monolithic integration with modulation-doped field-effect transistors. Furthermore, the results point to a possibility of achieving a bias-free detector for a gigabit-rate optical communication system.