High-performance Ge-on-insulator lateral p-i-n waveguide photodetectors for electronic–photonic integrated circuits at telecommunication wavelengths

Abstract

We report high-performance germanium-on-insulator (GeOI) waveguide photodetectors (WGPDs) for electronic–photonic integrated circuits (EPICs) operating at telecommunication wavelengths. The GeOI samples were fabricated using layer transfer and wafer-bonding techniques, and a high-quality Ge active layer was achieved. Planar lateral p-i-n WGPDs were fabricated and characterized, and they exhibited a low dark current of 0.1 µA. Strain-induced alterations in the optical properties were observed, resulting in an extended photodetection range up to λ = 1638 nm. This range encompasses crucial telecommunication bands. The WGPDs exhibited a high responsivity of 0.56 A/W and a high detectivity of D∗ = 1.87 ×109cmHz1/2W - 1 at 1550 nm. A frequency-response analysis revealed that increasing the bias voltage from −1 to −9 V enhances the 3-dB bandwidth from 31 to 49 MHz. This study offers a comprehensive understanding of GeOI WGPDs, fostering high-performance EPICs with implications for telecommunications and beyond.