Extensive Broadband Near-Infrared Emissions from GexSi1−x Alloys on Micro-Hole Patterned Si(001) Substrates

Abstract

Broadband near-infrared (NIR) luminescent materials have been continuously pursued as promising candidates for optoelectronic devices crucial for wide applications in night vision, environment monitoring, biological imaging, etc. Here, graded GexSi1−x (x = 0.1–0.3) alloys are grown on micro-hole patterned Si(001) substrates. Barn-like islands and branch-like nanostructures appear at regions in-between micro-holes and the sidewalls of micro-holes, respectively. The former is driven by the efficient strain relation. The latter is induced by the dislocations originating from defects at sidewalls after etching. An extensive broadband photoluminescence (PL) spectrum is observed in the NIR wavelength range of 1200–2200 nm. Moreover, the integrated intensity of the PL can be enhanced by over six times in comparison with that from the reference sample on a flat substrate. Such an extensively broad and strong PL spectrum is attributed to the coupling between the emissions of GeSi alloys and the guided resonant modes in ordered micro-holes and the strain-enhanced decomposition of alloys during growth on the micro-hole patterned substrate. These results demonstrate that the graded GexSi1−x alloys on micro-hole pattered Si substrates may have great potential for the development of innovative broadband NIR optoelectronic devices, particularly to realize entire systems on a Si chip.

Hexagonal-Ge Nanostructures with Direct-Bandgap Emissions in a Si-Based Light-Emitting Metasurface

“…In general, the smaller QDs, the less strain relaxation . Accordingly, the lattice mismatch between Ge and Si facilitates the formation of defects, involving stacking faults. − For multilayer growth of LTGe, the accumulation of misfit strain energy promotes the formation of the big QDs with a larger R ( R = 0.20), as demonstrated in Figure (b). This is consistent with previous reports. , Meanwhile, it also stimulates the formation of stacking faults in subsequent LTGe.…”

Unique hexagonal-Ge nanostructures with direct-bandgap emissions in Si-based light-emitting metasurface

“…28 Accordingly, the lattice mismatch between Ge and Si facilitates the formation of defects, involving stacking faults. [29][30][31][32] For multilayer growth of LTGe, the accumulation of mis t strain energy promotes the formation of the big QDs, as demonstrated in Fig. 1b.…”

Nanotechnologies and Nanomaterials: Selected Papers from CCMR

“…Additionally, the emission efficiency has been noticeably boosted by intensified hole injection (contribution 39) and spatial light modulation (contribution 40,41) with the existence of nanomaterials for light emitting and terahertz devices. In addition to light-emitting devices, nanomaterials have been widely witnessed in energy conversion devices and the synthesis of nanocomposites (contribution 42-44), and elaborately designed (contribution 45) nanostructures provide a facile approach for the enhancement of the conversion efficiency for Li-ion batteries and solar cells.…”