Extended-SWIR Photodetection in All-Group IV Core/Shell Nanowires

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.O.M. acknowledges support from NSERC Canada (Discovery, SPG, and CRD Grants), Canada Research Chairs, Canada Foundation for Innovation, Mitacs, PRIMA Québec, and Defence Canada (Innovation for Defence Excellence and Security, IDEaS). L.L acknowledges support from the China Scholarship Council (CSC). S.A. acknowledges support from Fonds de recherche du Québec-Nature et technologies (FRQNT, PBEEE scholarship). ICN2 acknowledges funding from Generalitat de Catalunya 2017 SGR 327. ICN2 is supported by the Severo Ochoa program from Spanish MINECO (grant No. SEV-2017-0706) and is funded by the CERCA Programme/Generalitat de Catalunya. S.M. and J.A. acknowledge the use of instrumentation as well as the technical advice provided by the National Facility ELECMI ICTS, node “Laboratorio de Microscopías Avanzadas” at the University of Zaragoza. S.M. and J.A. also acknowledge support from the CSIC Research Platform on Quantum Technologies PTI-001