Flexible InGaAs Photodetector With High-Speed Detection and Long-Term Stability

Flexible photodetectors have garnered extensive research interest due to their potential applications in optical communications, sensing, and wearable systems. However, their operating frequencies have been limited to less than 10 MHz, which falls significantly below the requirements for certain applications. Here, we present a high-performance flexible photodetector based on InGaAs nanomembrane fabricated on a flexible plastic foil, where epitaxial layers are bonded with adhesives before being lifted from the parent InP substrate via a simple wet etching step. No mechanical polishing is involved, reducing the complexity of the fabrication procedure. The flexible photodetector exhibits impressive characteristics, including a low dark current of 801 pA, a responsivity of 0.51 A/W, a high detectivity of 5.65 × 10 ¹⁰ Jones, and a linear dynamic range over 70 dB at an applied voltage of 6 V in 1550 nm. Furthermore, we have prioritized efficient and high-speed collection of photogenerated carriers by optimizing the design of interdigitated detection electrodes. Dynamic measurements indicate that the photodetector surpasses a 3-dB bandwidth of 2.03 GHz, enabling it to support a data communication rate of 4 Gb/s. Additionally, this flexible photodetector demonstrates a wide operational wavelength range, covering nearly the entire telecom band from 1260 nm to 1620 nm, in both its planar state and half-cylindrically curved shape. More importantly, the obtained photodetector maintains high performance with long-term thermal and mechanical stability, holding great potential for developing advanced high-speed optoelectronics in wearable devices.