Direct Bandgap Emission from Hexagonal Ge and SiGe Alloys

Abstract

Silicon crystallized in the usual cubic (diamond) lattice structure has dominated the electronics industry for more than half a century. However, cubic silicon (Si), germanium (Ge) and SiGe-alloys are all indirect bandgap semiconductors that cannot emit light efficiently. Accordingly, achieving efficient light emission from group-IV materials has been a holy grail in silicon technology for decades and, despite tremendous efforts, it has remained elusive. Here, we demonstrate efficient light emission from direct bandgap hexagonal Ge and SiGe alloys. We measure a subnanosecond, temperature-insensitive radiative recombination lifetime and observe a similar emission yield to direct bandgap III-V semiconductors. Moreover, we demonstrate how by controlling the composition of the hexagonal SiGe alloy, the emission wavelength can be continuously tuned in a broad range, while preserving a direct bandgap. Our experimental findings are shown to be in excellent quantitative agreement with the ab initio theory. Hexagonal SiGe embodies an ideal material system to fully unite electronic and optoelectronic functionalities on a single chip, opening the way towards novel device concepts and information processing technologies.

arXiv comment25 pages,5 main figures, 7 supplementary figures

References in corpus (8)

• Restoring the density-gradient expansion for exchange in solids and surfaces
• Generalized gradient approximation for solids and their surfaces
• Multidimensional quantum entanglement with large-scale integrated optics
• Attojoule Optoelectronics for Low-Energy Information Processing and Communications: a Tutorial Review
• xrayutilities: A versatile tool for reciprocal space conversion of scattering data recorded with linear and area detectors
• Accurate electronic and optical properties of hexagonal germanium for optoelectronic applications
• Electronic Structure and Optical Properties of the Lonsdaleite Phase of Si, Ge and diamond
• Radiation efficiency of heavily doped bulk n-InP semiconductor

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• Giant optical oscillator strengths in perturbed hexagonal germanium
• Extrinsic doping in group IV hexagonal-diamond type crystals
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• Pnictogens Allotropy and Phase Transformation during van der Waals Growth
• Atomistic insights into ultrafast SiGe nanoprocessing
• Superconductivity in Substitutional Ga-Hyperdoped Ge Epitaxial Thin Films
• Training and pattern recognition by an opto-magnetic neural network
• Investigation of Lasing in Highly Strained Germanium at the Crossover to Direct Band Gap
• Optical absorption in hexagonal-diamond Si and Ge nanowires: insights from STEM-EELS experiments and ab initio theory
• Localized State-Induced Enhanced Intrinsic Phonon-Free Optical Transition in Silicon Nanocrystals
• Formation of Micrometer-Sized Textured Hexagonal Silicon Crystals via Nanoindentation
• Femtosecond Laser Crystallization of Ultrathin a-Ge Films in Multilayer Stacks with Silicon Layers
• Interaction of dopants with the I${}_3$-type basal stacking fault in hexagonal-diamond Si
• Humble planar defects in SiGe nanopillars
• Electronic structure of Humble defects in Ge and Ge${}_{0.8}$Si${}_{0.2}$
• Acoustic phonons, spin-phonon coupling and spin relaxation via the lattice reorientation mechanism in hexagonal germanium nanowires
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• Multi-scale characterization of hexagonal Si-4H: a hierarchical nanostructured material
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