Dual-Functional Triangular-Shape Micro-Size Light-Emitting and Detecting Diode for On-Chip Optical Communication in the Deep Ultraviolet Band

Abstract

Light-emitting diodes and photodiodes, often acting as transmitters and receivers, are two key optical components for constructing an optical communication system. Recently, solar-blind optical wireless communication (SB-OWC) has emerged as a promising free-space communication platform due to its unique advantages, including low background noise, high security, and non-line-of-sight ability. However, the development of deep ultraviolet (DUV) emitters and detectors is still in its early stages with relatively low efficiency and poor detection capability, which hampers the further progress of SB-OWC. Herein, a triangular-shaped micro-sized diode (T-μ-diode) is reported that can significantly boost its DUV emission and detection performance compared with a regular circular-shaped micro-diode (C-μ-diode) due to improved current injection and enhanced light extraction/absorption behavior. Specifically, the T-μ-diodes demonstrate superior light output power with a −3 dB modulation bandwidth over 566 MHz operating at an extremely high current density of 2 kA cm⁻² while possessing a higher photo-responsivity of ≈160 mA W⁻¹ with a faster response speed of 5.1 ns, surpassing the traditional C-μ-diodes in both light emitting and detecting modes. Importantly, a bidirectional on-chip data transmission system is realized by simply switching the operation mode of two T-μ-diodes monolithically fabricated on the same platform with boosted emission and detection functionalities.