Printed GaAs Microstructures‐Based Flexible High‐Performance Broadband Photodetectors

Abstract Nano/microstructures of compound semiconductors such as gallium arsenide (GaAs) demonstrate enormous potential for advanced photonic technologies as they provide realistic means for miniaturization of optoelectronic devices that feature better performance and low power consumption. However, intimately integrating them onto flexible substrates is challenging and restricts their use in the next generation of applications such as wearables and soft robotics. Herein, printed arrays of well‐defined and laterally aligned semi‐insulating (undoped) and doped GaAs microstructures are presented to develop high‐performance flexible broadband photodetectors. The direct roll transfer printed GaAs microstructures‐based photodetectors exhibit excellent performance under ultraviolet and near‐infrared illumination, including ultrafast response (2.5 ms) and recovery (8 ms) times, high responsivity (>10⁴ AW^–1), detectivity (>10¹⁴ Jones), external quantum efficiency (>10⁶), and photoconductive gain (>10⁴) at low operating voltage of 1 V. The achieved performance is among the best reported for broadband photodetectors but with an added benefit of the developed devices having a flexible form factor. Further, the photodetectors show stable performance under mechanical bending (500 cycles) and twisting loading. The developed materials and manufacturing route can enable high‐speed communications and computation via high‐performance flexible electronics and optoelectronics and transform numerous emerging applications such as wearable systems and internet of things.