@article{BalderasValadezAntunezOliveMendezetal.2017,
  author    = {Balderas-Valadez, Ruth Fabiola and Antunez, E. E. and Olive-Mendez, Sion Federico and Pacholski, Claudia and Campos-Alvarez, Jose and Bokhimi, Xim and Agarwal, V.},
  title     = {Porous silicon pillar and bilayer structure as a nucleation center for the formation of aligned vanadium pentoxide nanorods},
  series = {Ceramics International},
  volume    = {43},
  journal   = {Ceramics International},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {0272-8842},
  doi       = {10.1016/j.ceramint.2017.03.114},
  pages     = {8023 -- 8030},
  year      = {2017},
  abstract  = {Porous silicon single layer (PSM), bilayer (PSB) and pillar (PSP) structures have been evaluated as nucleation centers for vanadium pentoxide (V2O5) crystals. Deposition of vanadium precursor over different substrates (drop casting technique), followed by annealing treatment under Ar-H-2 (5\% H-2) atmosphere, induced crystallization of vanadium oxide. With respect to c-Si/SiO2 substrate, V2O5 nanorods with relatively large aspect ratio were formed over and within PSP structures. On the other hand, pores in PSM and PSB were found to be filled with relatively smaller crystals. Additionally, PSB provided a nucleation substrate capable to align the nanocrystals in a preferential orientation, while V2O5 crystals grown on PSP were found to be randomly aligned around the nanoporous pillar microstructure. Nanorods and nanocrystals were identified as V2O5 by temperature-controlled XRD measurements and evidence of their crystalline nature was observed via transmission electron microscopy. A careful analysis of electronic microscopy images allows the identification of the facets composing the ends of the crystals and its corresponding surface free energy has been evaluated employing the Wulff theorem. Such high surface area composite structures have potential applications as cathode material in Lithium-ion batteries.},
  language  = {en}
}
@article{BalderasValadezEstevezEspinozaSalazarKurietal.2018,
  author    = {Balderas-Valadez, Ruth Fabiola and Estevez-Espinoza, J. O. and Salazar-Kuri, U. and Pacholski, Claudia and Mochan, Wolf Luis and Agarwal, Vivechana},
  title     = {Fabrication of ordered tubular porous silicon structures by colloidal lithography and metal assisted chemical etching},
  series = {Applied surface science : a journal devoted to applied physics and chemistry of surfaces and interfaces},
  volume    = {462},
  journal   = {Applied surface science : a journal devoted to applied physics and chemistry of surfaces and interfaces},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0169-4332},
  doi       = {10.1016/j.apsusc.2018.08.120},
  pages     = {783 -- 790},
  year      = {2018},
  abstract  = {Fabrication of well-ordered porous silicon tubular structures using colloidal lithography and metal assisted chemical etching is reported. A continuous hexagonal hole/particle gold pattern was designed over monocrystalline silicon through deposition of polyNIPAM microspheres, followed by the surface decoration with gold nanoparticles and thermal treatment. An etching reaction with HF, ethanol and H2O2 dissolved the silicon in contact with the metal nanoparticles (NP), creating a porous tubular array in the "off-metal area". The morphological characterization revealed the formation of a cylindrical hollow porous tubular shape with external and internal diameter of approx. 900 nm and 400 nm respectively, though it can be tuned to other desired sizes by choosing an appropriate dimension for the microspheres. The porous morphology and optical properties were studied as a function of resistivity of silicon substrates. Compared to two different gold templates on cSi and nontubular porous pillar structures, porous silicon tubular framework revealed a maximum surface enhanced Raman scattering enhancement factor of 10(6) for the detection of 6-mercaptopurine (6-MP). Due to the large surface area available for any surface modification, open nanostructured platforms such as those studied here have potential applications in the field of reflection/photoluminescene and SERS based optical bio-/chemical sensors.},
  language  = {en}
}