Grating-coupled mid-infrared light emission from tensilely strained germanium nanomembranes

• Published in: Applied physics letters Vol. 103; no. 20; p. 201114
• Main Authors: Boztug, Cicek, Sánchez-Pérez, José R., Yin, Jian, Lagally, Max G., Paiella, Roberto
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 11-11-2013
• Subjects: Applied physics; Arrays; Diffraction; GERMANIUM; GRATINGS; Holes; Infrared lasers; Infrared signatures; LASERS; Light emission; LUMINESCENCE; NANOSCIENCE AND NANOTECHNOLOGY; Nanostructure; Optoelectronics; Photonic crystals; RED SHIFT; SEMICONDUCTOR MATERIALS; Semiconductors; STRAINS; STRESSES; Tensile strain; WAVELENGTHS
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.4830377

Mechanically stressed nanomembranes are used to demonstrate mid-infrared interband light emission from Ge within the 2.1–2.5 μm atmospheric transmission window. Large biaxial tensile strain is introduced in these samples to convert Ge into a (near-) direct-bandgap semiconductor and to red-shift its luminescence. A diffractive array of Ge pillars is used to outcouple the long-wavelength interband radiation, which is otherwise primarily emitted in the sample plane. An order-of-magnitude strain-induced enhancement in radiative efficiency is also reported, together with the observation of luminescence signatures associated with photonic-crystal cavity modes. These results are promising for the development of silicon-compatible lasers for mid-infrared optoelectronics applications.