2026
Journal of Alloys and Compounds, Q1
Статьи в журналах
Volume 1080, 25 September 2026, 190660
V.M. Il’yaschenko, D.V. Pavlov, A.V. Gerasimenko, A.K. Gutakovskii, A.A. Kuchmizhak, A.V. Shevlyagin / Black magnesium germanide: From industry-feasible Ge surface texturing to Mg2Ge/Ge self-powered SWIR photodetector demonstration // Journal of Alloys and Compounds 1080 (2026) 190660.
The narrow bandgap of germanium (Ge) opens up the possibility of developing an optical platform with improved near‑infrared performance. By implementing a surface texturing protocol, one can expect to obtain black Ge with broader spectral antireflection. To further improve its light‑trapping performance and extend its "blackness" toward the mid‑infrared, we propose a simple and scalable method for wet‑chemical surface texturing of Ge, which is an adaptation of the silicon RCA cleaning protocol and results in the formation of Ge pyramids (text‑Ge). Vacuum deposition of a magnesium germanide (Mg2Ge) film as a top layer on text‑Ge further enhances infrared absorption and light-trapping due to the intermediate refractive index of Mg2Ge. The results of crystal structure, phase composition, and optical investigations confirm the successful formation of the Mg2Ge/text‑Ge heterostructure, termed black magnesium germanide (b‑Mg2Ge), with greatly reduced average reflection (~4.2%) in the 450–3000 nm region. A self‑powered photodetector fabricated from b‑Mg2Ge shows a significant improvement in the operating spectral range down to 3 µm compared to Ge alone, while maintaining high peak photoresponse above 1 A/W and detectivity of 1010 Jones together with an operating speed in the tens‑of‑microseconds range. A linear dynamic range of 47 dB and a 3‑dB bandwidth of 37 kHz at 1550 nm further confirm the device's suitability for quantitative high‑speed photodetection. The demonstrated results suggest that b‑Mg2Ge could be a material of choice for the development of advanced optoelectronic devices.
https://doi.org/10.1016/j.jallcom.2026.190660