Epitaxial Growth of Germanium on Silicon for Light Emitters

National Basic Research Program of China [2007CB613404, 2012CB933503]; National Natural Science Foundation of China [61036003, 60837001, 61176092]; Fundamental Research Funds for the Central Universities [2010121056]This paper describes the role of Ge as an enabler for light emitters on a Si platform. In spite of the large lattice mismatch of similar to 4.2% between Ge and Si, high-quality Ge layers can be epitaxially grown on Si by ultrahigh-vacuum chemical vapor deposition. Applications of the Ge layers to near-infrared light emitters with various structures are reviewed, including the tensile-strained Ge epilayer, the Ge epilayer with a delta-doping SiGe layer, and the Ge/SiGe multiple quantum wells on Si. The fundamentals of photoluminescence physics in the different Ge structures are discussed briefly

Preparation for SiGe/Si heterogeneous nanostructures via a two-step approach strategy

SiGe/Si heterogeneous nanostructures were prepared by electrochemical anodization of SiGe/Si MQWs. Structural and optical properties of the materials were characterized. The origin of the photoluminescence from the heterogeneous nanostructures at room temperature is discussed

Texture Evolution and Grain Competition in NiGe Film on Ge(001)

National Natural Science Foundation of China [61176092, 61036003, 60837001]; National Basic Research Program of China [2012CB933503, 2013CB632103]; Ph. D. Programs Foundation of Ministry of Education of China [20110121110025]; Fundamental Research Funds for the Central Universities [2010121056]; Natural Science Foundation of Fujian Province of China [2012J01284]; Opened Fund of the State Key Laboratory on Integrated Optoelectronics [2011KFB004]To understand the agglomeration mechanism of NiGe films grown on Ge(001), texture structures of NiGe films are revealed by X-ray pole figure measurement. Two preferred epitaxial orientations of the NiGe grains are identified to be NiGe(4 (5) over bar4) II Ge(001) NiGe[(1) over bar 01] II Ge[110] and NiGe(130) II Ge(001) NiGe[002] II Ge[110]. The component of the first epitaxial alignment becomes dominating and the latter diminishing with increasing annealing temperature. The NiGe grains of the second epitaxial alignment are unstable and diminishing at high temperature due to the relatively higher interface/surface energy. The competition of grains with various epitaxial orientations has made a significant contribution to film agglomeration. (C) 2013 The Japan Society of Applied Physic

Self-mask fabrication of uniformly orientated SiGe island/SiGe/Si hetero-nanowire arrays with controllable sizes

National Natural Science Foundation of China [61176050, 61036003, 61176092]; Fundamental Research Funds for the Fujian province of China [2012H0038]; National Basic Research Program of China [2012CB933503, 2013CB632103]; Fundamental Research Funds for the Central Universities [2010121056]We report the synthesis of SiGe island/SiGe/Si hetero-nanowire arrays using laser-induced SiGe islands as templates followed by Ar ion beam etching (IBE). Firstly, single crystal SiGe islands with an average aspect ratio of 0.96 are prepared by pulse laser irradiation of amorphous Ge film on Si substrate. It is interesting to note that these SiGe islands can serve as masks, and uniformly orientated SiGe island/SiGe/Si nanowires can be fabricated by Ar IBE. Moreover, the diameters of the hetero-nanowires can be well-controlled by the size of the SiGe islands determined by the energy density of the pulse laser during the crystallization. Our experiments show the unique nonlithographic self-mask method and demonstrate the mass production of SiGe island/SiGe/Si hetero-nanowire arrays which may find applications in nanodevices

Production of He-4 and (4) in Pb-Pb collisions at root(NN)-N-S=2.76 TeV at the LHC

Results on the production of He-4 and (4) nuclei in Pb-Pb collisions at root(NN)-N-S = 2.76 TeV in the rapidity range vertical bar y vertical bar <1, using the ALICE detector, are presented in this paper. The rapidity densities corresponding to 0-10% central events are found to be dN/dy4(He) = (0.8 +/- 0.4 (stat) +/- 0.3 (syst)) x 10(-6) and dN/dy4 = (1.1 +/- 0.4 (stat) +/- 0.2 (syst)) x 10(-6), respectively. This is in agreement with the statistical thermal model expectation assuming the same chemical freeze-out temperature (T-chem = 156 MeV) as for light hadrons. The measured ratio of (4)/He-4 is 1.4 +/- 0.8 (stat) +/- 0.5 (syst). (C) 2018 Published by Elsevier B.V.Peer reviewe

Enhanced Osteogenesis by a Biomimic Pseudo-Periosteum-Involved Tissue Engineering Strategy

Elaborating a bone replacement using tissue-engineering strategies for bone repair seems to be a promising remedy. However, previous platforms are limited in constructing three-dimensional porous scaffolds and neglected the critical importance of periosteum (a pivotal source of osteogenic cells for bone regeneration). We report here an innovative method using the periosteum as a template to replicate its exquisite morphologies onto the surfaces of biomaterials. The precise topographic cues (grooved micropatterns) on the surface of collagen membrane inherited from the periosteum effectively directed cell alignment as the way of natural periosteum. Besides, we placed the stem-cell and endothelial-cell-laden collagen membrane (pseudo-periosteum) onto a three-dimensional porous scaffold. The pseudo-periosteum-covered scaffolds showed remarkable osteogenesis when compared with the pseudo-periosteum-free scaffolds, indicating the significant importance of pseudo-periosteum on bone regeneration. This study gives a novel concept for the construction of bone tissue engineering scaffold and may provide new insight for periosteum research