Large-scale fabrication of single-phase Er2SiO5 nanocrystal aggregates using Si nanowires

Abstract

Single-phase Er 2 SiO 5 nanocrystal aggregates were produced on a large scale using Si nanowire ͑Si-NW͒ arrays as templates. A dense array of Si-NWs was grown by vapor-liquid-solid mechanism using Au catalyst on Si ͑111͒ substrate. Afterwards, ErCl 3 ·6H 2 O dissolved ethanol solution was spin coated and annealed first at 900°C for 4 min in a flowing N 2 /O 2 environment and then at 1200°C in a flowing Ar environment for 3 min. X-ray diffraction, scanning electron microscope, and high-resolution transmission electron microscope measurements indicate that due to the use of Si-NWs, such a short annealing procedure is sufficient to completely transform the Er-coated Si-NWs into a thick, large-area aggregate of pure, single-phase to There is a strong and growing interest in developing Si photonics that can integrate the fast, lossless information carrying capacity of photonics with Si integrated circuit technology to overcome the impending "interconnect bottleneck." 1 In particular, a great effort has been made in developing a Si-based light source, especially a laser, that can overcome the inherent limitation of the indirect band gap of Si. 1,2 Among the many possible ways of obtaining light emission from Si, 3-5 using the rare earth ion Er 3+ as an optical dopant has attracted a special attention because of its ability to provide light at 1.5 m that is compatible not only with optical telecommunication but also with silicon-oninsulator based Si microphotonic devices. 5,6 Furthermore, Er doping has a history of proven success in providing optical gain and lasing when doped into silica fiber amplifiers. 7 The intra-4f transition of Er 3+ that gives rise to the 1.5 m luminescence is parity forbidden and occurs due to the effects of the crystal field surrounding Er 3+ ions. This leads to long luminescence lifetimes and, when doped into an amorphous host such as silica, large inhomogeneous broadening of the atomic luminescence peak that allow for low-noise, broadband amplification capability of EDFAs. Unfortunately, the same qualities can lead to severe limitations for its applicability for Si photonics that requires a large optical gain in a limited wavelength range from a micrometer-sized volume, since the combination of long luminescence lifetimes and a broad luminescence peak results in a low gain cross section at a particular wavelength. Increasing the gain requires a very high Er concentration, but the concentration of optically active Er that can be doped into a host material without clustering is limited, even for an amorphous host such as silica. 8,9 Another way of increasing the gain cross section per wavelength is reducing the inhomogeneous broadening of Er 3+ luminescence by using a crystalline host matrix, but even in that case, controlling the location of Er 3+ ions down to atomic levels is difficult. 10 A rather interesting alternative to Er doping that can overcome these difficulties is to raise the Er concentration so high that a stable, Er rich crystalline phase can form. In particular, crystalline ra...

Growth, processing, and optical properties of epitaxial Er_2O_3 on silicon

“…In this work we describe the growth, processing, and optical properties of single-crystal Er 2 O 3 -on-Si (EOS). Similar to stoichiometric polycrystalline Er 3+ materials [15][16][17][18][19][20], EOS allows for a 100-fold increase in Er 3+ concentration over conventional Er-doped glasses [21], making it an attractive material for on-chip emission and amplification in the 1550-nm wavelength band. Developed simultaneously for optoelectronic [22] and high-κ dielectric [23] applications, epitaxially grown Er 2 O 3 films can be incorporated into precisely controlled heterostructures and superlattices, which may also allow for efficient electrical injection.…”

Real-time synchrotoron radiation X-ray diffraction and abnormal temperature dependence of photoluminescence from erbium silicates on SiO2/Si substrates

“…[1][2][3][4][5][6][7][8] In the erbium compounds, the density of erbium ions is 10 22 atoms/cm 3 , which is orders of magnitude greater than that typically obtained by Er ion implantation in silicon substrate, allowing access to a large number of emitting centers.…”

“…Previous work revealed that the processes in the growth methods significantly affect the photoluminescence (PL) intensities of Er +3 ions in the materials. [1][2][3][4][5][6][7][8] According to Ref. 7, for example, the PL intensity of Er 2 O 3 grown on Si and SiO 2 by magnetron sputtering becomes large with an increase of annealing temperature up to 1200…”

Optical properties of Y2O3 thin films doped with spatially controlled Er3+ by atomic layer deposition

“…Some of these methods include utilization of sensitizers such as silicon nanoclusters, [7][8][9][10][11] incorporation of Er in Si x N y , 12 co-implantation of silver in silica glass, 13 preparation of multilayers of Er-doped SiO 2 with silicon rich silicon dioxide ͑SRSO͒, [14][15][16] and synthesis of Er-doped oxide nanostructures. 17,18 Much research effort has also been directed in determining the absorption cross sections for these material systems. For example, the photoluminescence ͑PL͒ rise time measurements have been used to determine an enhanced effective excitation absorption cross section of 1.1 ϫ 10 −16 cm of Er in SiO 2 and the slight improvement in peak absorption cross section with Si inclusion, SiO 2 turns out to be an unsuitable host material for miniaturizing compact planar optical waveguides, leaving groups to turn to alternative host materials.…”