Printing of Nano- to Chip-Scale Structures for Flexible Hybrid Electronics

Abstract

Flexible hybrid electronics (FHE) offers potential for fast computation and communication needed in applications such as human–machine interfaces, electronic skin, etc. FHE typically comprises devices that can vary from nano- to chip scale, and their integration using a common process is often challenging. Herein, a printed electronics route is presented to integrate the ultrathin chips (chip-scale) and nanowires (NWs)-based electronic layers (nanoscale) on the same substrate. The fabrication process is categorized into three stages: i) direct transfer printing of ultrathin chips (UTCs), ii) contact printing of nanoscale structures, and iii) metal printing using the direct ink write (DIW) method to define electrodes/interconnects. The UTC printing process is carefully optimized by studying the performance of transistors present on them. Electrical data collected from 14 transistors located on 3 different chips show negligible variation in performance after they are transfer printed—thus confirming the efficacy of the printing technique. The superior grade quality of ZnO-NWs-based electronic layers printed on the same substrate is also demonstrated by constructing UV photodetectors using DIW printing. The photodetectors show high responsivity (≈2 × 107 A W−1) and specific detectivity (≈5 × 1015 Jones) at a low UV intensity of 0.5 µW cm−2.