Extended-SWIR Photodetection in All-Group IV Core/Shell Nanowires
Lu Luo, Simone Assali, Mahmoud R. M. Atalla, Sebastian Koelling, Anis Attiaoui, Gérard Daligou, Sara Martí‐Sánchez, Jordi Arbiol, Oussama Moutanabbir
Abstract
Group IV Ge1–xSnx semiconductors hold the premise of enabling broadband silicon-integrated infrared optoelectronics due to their tunable band gap energy and directness. Herein, we exploit these attributes along with the enhanced lattice strain relaxation in Ge/Ge0.92Sn0.08 core/shell nanowire heterostructures to implement highly responsive room-temperature short-wave infrared nanoscale photodetectors. Atomic-level studies confirm the uniform shell composition and its higher crystallinity with respect to thin films counterparts. The demonstrated Ge/Ge0.92Sn0.08 p-type field-effect nanowire transistors exhibit superior optoelectronic properties achieving simultaneously relatively high mobility, high ON/OFF ratio, and high responsivity, in addition to a broadband absorption in the short-wave infrared range. Indeed, the reduced band gap of the Ge0.92Sn0.08 shell yields an extended cutoff wavelength of 2.1 μm, with a room-temperature responsivity reaching 2.7 A/W at 1550 nm. These results highlight the potential of Ge/Ge1–xSnx core/shell nanowires as silicon-compatible building blocks for nanoscale-integrated infrared photonics.