A. Sanchez-Martinez

Bio: A. Sanchez-Martinez is an academic researcher from Autonomous University of Zacatecas. The author has contributed to research in topics: Nanoparticle & X-ray photoelectron spectroscopy. The author has an hindex of 8, co-authored 21 publications receiving 192 citations. Previous affiliations of A. Sanchez-Martinez include CINVESTAV & Universidad Veracruzana.

Ferroelectric Materials for Solar Energy Conversion: Photoferroics Revisited

Abstract: The application of ferroelectric materials (i.e. solids that exhibit spontaneous electric polarisation) in solar cells has a long and controversial history. This includes the first observations of the anomalous photovoltaic effect (APE) and the bulk photovoltaic effect (BPE). The recent successful application of inorganic and hybrid perovskite structured materials (e.g. BiFeO3, CsSnI3, CH3NH3PbI3) in solar cells emphasises that polar semiconductors can be used in conventional photovoltaic architectures. We review developments in this field, with a particular emphasis on the materials known to display the APE/BPE (e.g. ZnS, CdTe, SbSI), and the theoretical explanation. Critical analysis is complemented with first-principles calculation of the underlying electronic structure. In addition to discussing the implications of a ferroelectric absorber layer, and the solid state theory of polarisation (Berry phase analysis), design principles and opportunities for high-efficiency ferroelectric photovoltaics are presented.

C-,N- and S-Doped TiO2 Photocatalysts: A Review

Abstract: This article presents an overview of the reports on the doping of TiO2 with carbon, nitrogen, and sulfur, including single, co-, and tri-doping. A comparison of the properties of the photocatalysts synthesized from various precursors of TiO2 and C, N, or S dopants is summarized. Selected methods of synthesis of the non-metal doped TiO2 are also described. Furthermore, the influence of the preparation conditions on the doping mode (interstitial or substitutional) with reference to various types of the modified TiO2 is summarized. The mechanisms of photocatalysis for the different modes of the non-metal doping are also discussed. Moreover, selected applications of the non-metal doped TiO2 photocatalysts are shown, including the removal of organic compounds from water/wastewater, air purification, production of hydrogen, lithium storage, inactivation of bacteria, or carbon dioxide reduction.

Photo-induced Groth of Dielectrics with Excimer Lamps

Abstract: Abstract The underlying principles and properties of vacuum ultraviolet (VUV) and ultraviolet (UV) radiation (excimer lamps), generated by a dielectric barrier discharge in a rare-gas (Rg) or a mixture of Rg and halogen, are discussed. Compared with conventional sources, these excimer lamps offer narrow-band radiation at various wavelengths from 108–354 nm and over large areas with high efficiencies and high power densities. The variety of available wavelengths offers an enormous potential for new industrial applications in materials processing. Previously, photo-oxidation of silicon, germanium and silicon–germanium and photo-deposition of single- and multi-layered films of silicon oxide, silicon nitride, and silicon oxynitride have been demonstrated by using excimer lamps. This paper reviews the progress on excimer lamp-assisted growth of high dielectric constant (Ta 2 O 5 , TiO 2 and PZT) and low dielectric constant (polyimide and porous silica) thin films by photo-CVD and sol–gel processing, summarizes the properties of photo-induced growth of Ta 2 O 5 films and discusses the effect and mechanism of low temperature UV annealing with 172 nm radiation. Metal oxide semiconductor capacitors based on the photo-induced Ta 2 O 5 films grown directly on Si at low temperatures exhibit excellent electrical properties. Leakage current densities as low as 5.2×10 −7 A cm −2 and 2.41×10 −7 A cm −2 at 1 MV cm −1 have been achieved for the as-grown Ta 2 O 5 films deposited by photo-induced sol–gel processing and photo-CVD, respectively-several orders of magnitude lower than for any other as-grown films prepared by any other technique. A subsequent low temperature (400°C) UV annealing step improves these to 10 −8 A cm −2 . These values are comparable to those only previously achieved for films annealed at high temperatures between 600°C and 1000°C. These properties make the photo-induced growth of Ta 2 O 5 layers suitable alternative to SiO 2 for high density DRAM application.