Fast UV–vis–NIR photoresponse of self-oriented F₁₆CuPc nanoribbons

Controlling the vapor-deposited nanoribbons to grow along a consistent orientation will enable the desired in situ integration of functional devices, representing a major technological advance compared to post-growth processing strategies. In this work, n-type F₁₆CuPc molecules are self-assembled into horizontally-oriented nanoribbons with a consistent growth axis after creating periodic hydrophobic nanogrooves on a sapphire surface. Consequently, electrodes are deposited directly on the growth substrate to enable in situ fabrication of photodetectors. Depending on the deposited electrodes, these horizontally-oriented nanoribbons are connected to form a monolithic photodetector with a large sensing area or an on-chip array of photodetectors with multiple detector units. This in situ integration strategy avoids potential structural damage and contamination from impurities associated with post-growth processing steps. Therefore, the vapor-deposited nanoribbons can retain their high quality during the device manufacturing process, which contributes to performance improvement. As a result, the in-situ integrated F₁₆CuPc photodetectors exhibit a sensitive response in the ultraviolet–visible–near-infrared (UV–vis–NIR) region. The response time is on the order of tens of milliseconds, the fastest record ever for the F₁₆CuPc-based photodetectors. Furthermore, statistics from an array of 6 × 6 photodetectors show little variation in their sensitivity and response time, and hence this in situ fabrication scheme will contribute to the implementation of on-chip integrated photodetectors with consistent performance based on bottom-up nanoribbons. Overall, this self-oriented growth provides a versatile option to achieve desired in-situ integrated functional devices based on bottom-up nanoribbons.