Woo Seungwan, Ryu Geunhwan, Kang Soo Seok, Kim Tae Soo, Hong Namgi, Han Jae-Hoon, Chu Rafael Jumar, Lee In-Hwan, Jung Daehwan, Choi Won Jun
Department of Materials Science and Engineering, Korea University, Seoul 02481, South Korea.
Center for Opto-Electronic Materials and Devices, Korea Institute of Science and Technology, Seoul 02792, South Korea.
ACS Appl Mater Interfaces. 2021 Nov 24;13(46):55648-55655. doi: 10.1021/acsami.1c14687. Epub 2021 Nov 15.
Current infrared thermal image sensors are mainly based on planar firm substrates, but the rigid form factor appears to restrain the versatility of their applications. For wearable health monitoring and implanted biomedical sensing, transfer of active device layers onto a flexible substrate is required while controlling the high-quality crystalline interface. Here, we demonstrate high-detectivity flexible InAs thin-film mid-infrared photodetector arrays through high-yield wafer bonding and a heteroepitaxial lift-off process. An abruptly graded InAlAs (0.5 < < 1) buffer was found to drastically improve the lift-off interface morphology and reduce the threading dislocation density twice, compared to the conventional linear grading method. Also, our flexible InAs photodetectors showed excellent optical performance with high mechanical robustness, a peak room-temperature specific detectivity of 1.21 × 10 cm-Hz/W at 3.4 μm, and excellent device reliability. This flexible InAs photodetector enabled by the heteroepitaxial lift-off method shows promise for next-generation thermal image sensors.
