R. Herino

University Joseph Fourier - Grenoble 1, Grenoble, Rhône-Alpes, France

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Publications (74)128.06 Total impact

  • MRS Online Proceeding Library 01/2011; 358. DOI:10.1557/PROC-358-619
  • MRS Online Proceeding Library 01/2011; 256. DOI:10.1557/PROC-256-215
  • W. Theiβ · P. Grosse · H. Münder · H. Lüth · R. Herino · M. Ligeon
    MRS Online Proceeding Library 01/2011; 283. DOI:10.1557/PROC-283-215
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    ABSTRACT: Highly porous silicon, well passivated via an anodic oxidation process, is a stable and efficient visible light emitter showing a 3% photoluminescence efficiency at room temperature. Luminescence decay times are on the order of 100 μs at room temperature and 10 ms at low temperature. Above room temperature the de-excitation is dominated by nonradiative processes well describe by a tunneling escape of carriers from confined regions. The `anomalous' luminescence behaviour showing a dramatic increase of the lifetimes upon cooling associated with a decrease of the intensity is explained by the temperature dependence of the effective radiative recombination rates due to a population redistribution among two excited states with very different radiative relaxation rates.
    MRS Online Proceeding Library 01/2011; 283. DOI:10.1557/PROC-283-241
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    ABSTRACT: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
    ChemInform 01/2010; 26(5). DOI:10.1002/chin.199505018
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    ABSTRACT: This paper presents preliminary results on the selective growth of three-dimensional (3D) micrometric metallic structures by the MOCVD technique. The D structure growth occurs by simply feeding the reactor gas phase with a conventional flow of metal-organic (MO), trimethyl-gallium (TMGa) molecules. Selectivity occurs at the substrate surface in which MO species travel tens of micrometers in order to build up the 3D structure. After the growth, these structures are nitrided in order to give GaN-related optical visible emission. Optical emission results are presented and discussed in this paper. Both 3D structures deposition and annealing experiments can be extended to other III–V materials.
    Journal of Crystal Growth 12/2004; 272(1):466-474. DOI:10.1016/j.jcrysgro.2004.09.002 · 1.70 Impact Factor
  • B. Gelloz · A. Bsiesy · R. Herino
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    ABSTRACT: Electrically induced photoluminescence (PL) quenching from reverse-biased p+-type porous silicon (PS) and forward biased oxidized n-type PS, as well as their dynamics, have been investigated. The two systems exhibit common properties. The energy selectivity of the PL quenching by the applied potential is much lower than with nonoxidized n-type PS. The PL quenching time is independent of the emission energy. It is governed by carrier injection into PS and is limited by the Helmoltz capacitance at the electrolyte–PS interface and the electrolyte resistivity. The PL recovery time is longer than the quenching time and increases as the emission energy decreases. It is limited by the transparency of the energy barrier (due to oxide in the case of oxidized n-type PS and the depletion region in the case of p+-type PS) at the PS–substrate interface. It is shown that electron storage into PS is possible for time in excess of several seconds depending on parameters such as the oxidation level, the PS thickness, and the electrolyte resistivity. © 2003 American Institute of Physics.
    Journal of Applied Physics 08/2003; 94(4):2381-2389. DOI:10.1063/1.1594266 · 2.18 Impact Factor
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    ABSTRACT: Anodic oxidation of porous silicon, the inner surface of which is covered by a thin layer of Ge, has been studied. The Ge layer is first oxidized during a time proportional to the amount of Ge, prior to oxidation of the porous silicon. It is shown how anodic oxidation can be used as a new method for the measurement of the amount of Ge incorporated into porous silicon pores. It is also a valuable technique for evaluating the homogeneity of the Ge coverage.
    physica status solidi (a) 05/2003; 197(1):123-127. DOI:10.1002/pssa.200306486 · 1.21 Impact Factor
  • H. Diesinger · A. Bsiesy · R. Hérino
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    ABSTRACT: A new experimental set-up has been developed which uses the environment of near field optical microscopy to locally induce photo-electrochemical reactions at a semiconductor surface in contact with an electrolyte. When the semiconductor is under reverse bias, illumination of the surface by the optical tip of the microscope creates photogenerated carriers which are separated by the electric field in the space charge region. The charge carriers which are driven to the surface can react with the surface atoms or with electro-active species diluted into the electrolyte. Depending on the electrolyte composition and owing to the polarization conditions, one can induce selected photo-electrochemical reactions which may result in the etching of the surface or in the deposition of different materials at the nanometer scale. Several examples of applications are given: the photo-current mapping of silicon surfaces patterned with porous silicon, the localized photo-induced etching of silicon at the submicron scale, and the nanostructuring of porous silicon by direct writing.
    physica status solidi (a) 05/2003; 197(2):561 - 565. DOI:10.1002/pssa.200306563 · 1.21 Impact Factor
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    H Diesinger · A Bsiesy · R Hérino · S Huant
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    ABSTRACT: A technique allowing near-field photocurrent (PC) mapping of silicon surfaces in contact with an electrolyte is presented. The illumination source is an optical fibre tip with a 100-nm aperture. A shear force detection system controls the tip-sample distance while scanning the tip across the silicon-electrolyte interface. Topographic and PC images on SiO2/Si mesas both show 300 nm resolution. It is shown that this PC contrast is induced by the tip-topography interaction and hence the PC resolution is limited by the resolution of the topography. Indeed, PC mapping on topography-less patterned porous-silicon/silicon samples shows that the lateral resolution is only limited by the aperture size which is of the order of 100 nm.
    Journal of Microscopy 05/2001; 202(Pt 1):223-8. DOI:10.1046/j.1365-2818.2001.00816.x · 2.33 Impact Factor
  • H. Diesinger · A. Bsiesy · R. Hérino
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    ABSTRACT: The application of a near-field optical device to the electrochemical deposition of submicron nickel dots on silicon is demonstrated. The silicon-electrolyte junction behaves like a Schottky diode where the electrolyte plays the role of the metal. The junction is reverse biased so that only a negligible dark current is flowing across the junction. The optical tip of the near-field device is used as a local lightsource to control a photocurrent on a submicron scale, which allows one to create submicron objects of nickel by locally triggering the electrochemical reduction of nickel ions. The effect of the lateral diffusion of the photogenerated carriers on the form of the deposited nickel dots is described by a two-dimensional carrier diffusion model.
    Journal of Applied Physics 01/2001; 90(9):4862-4864. DOI:10.1063/1.1405136 · 2.18 Impact Factor
  • Heinrich Diesinger · Ahmad Bsiesy · Roland Hérino · Serge Huant
    Journal of Applied Physics 01/2001; 89:5801-5801. DOI:10.1063/1.1372663 · 2.18 Impact Factor
  • Heinrich Diesinger · Ahmad Bsiesy · Roland Hérino
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    ABSTRACT: Detailed experimental procedure of an in situ photoelectrical technique applied to porous silicon absorption coefficient measurement is described. In this technique, the underlying silicon substrate is used as a photodetector of the monochromatic light intensity transmitted by the porous layer. In particular, the investigation of spectral range validity of this technique has evidenced that at high photon energy, the porous silicon photoluminescence (PL) is excited and contributes to the photocurrent. It is shown that this PL contribution can be readily separated from that of the directly transmitted light, providing two benefits: first, the high accuracy of the measurement remains unaffected by the PL at high excitation energy, which justifies the application to photon energy as high as 3 eV, and second, the PL component can be further exploited to measure the porous silicon PL quantum efficiency. Typical absorption coefficient spectra obtained by this technique are then recalled. They are discussed in the frame of a model based on the analysis of the absorption coefficient of an ensemble of different quantum-size silicon crystallites. © 2001 American Institute of Physics.
    Journal of Applied Physics 12/2000; 89(1):221-225. DOI:10.1063/1.1328785 · 2.18 Impact Factor
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    Roland Hérino
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    ABSTRACT: The open porous structure and the very large specific surface area of porous silicon have motivated scientists to introduce different materials into the pores, forming composite structures devoted to different applications relying on the luminescence properties or the sensing capability of the resulting nanostructures. In this paper, the various composite structures that have been formed from porous silicon layers in recent years are reviewed, by focusing on the different methods used for deposition: dry processes, impregnation by contact with a liquid, chemical bath deposition or electrochemical deposition. Special attention is given to the particular requirements and specific drawbacks of each process.
    Materials Science and Engineering B 01/2000; 69-70:70-76. DOI:10.1016/S0921-5107(99)00269-X · 2.17 Impact Factor
  • L Montès · R Hérino
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    ABSTRACT: The incorporation of ZnSe into luminescent porous silicon layers (PSL) by electrochemical co-deposition of Zn and Se is described by focusing on the critical parameters related to the specific nature of porous silicon. The PSL photoluminescence is monitored during the growth of ZnSe to reveal the effects of the process on the optical properties of the structure, allowing an in-situ characterization of the growth. The structure and chemical composition of the resulting nanostructures are investigated by transmission electron microscopy (TEM) and chemical microanalysis which show homogeneous incorporation of ZnSe inside the porous matrix with no segregation. Crystallization of ZnSe by subsequent thermal annealing is also studied and preliminary characterizations of the electrical properties of the resulting nanocomposite structures are presented.
    Materials Science and Engineering B 01/2000; 69:136-141. DOI:10.1016/S0921-5107(99)00234-2 · 2.17 Impact Factor
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    ABSTRACT: A new in-situ technique allowing accurate measurements of the porous silicon optical absorption coefficient α is described. This technique is based on the measurement of the photocurrent generated in the substrate under light excitation through the porous layer, and does not require to dry the porous layer or to detach it from the silicon substrate. The absorption spectra of p-type and p+-type porous layers have been measured from 1.5 to 3 eV for a wide range of porosities. The results are analysed by focusing on the possible effect of quantum confinement. It is concluded that confinement does not account for the α dependence upon porosity over the full investigated range, but that it is only responsible for the faster decrease of α towards the absorption edge that is observed for highly porous and luminescent layers. An absorption model is developed that takes into account the effect of the quantum confinement on the density of states of the silicon nanocrystallites and that complies with the observed spectral behavior.
    Materials Science and Engineering B 01/2000; 69:167-170. DOI:10.1016/S0921-5107(99)00251-2 · 2.17 Impact Factor
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    ABSTRACT: The incorporation of cadmium sulfide into fresh and methyl-grafted porous silicon layers is investigated. Methyl grafting is obtained by an electrochemical method. Cadmium sulfide deposition is achieved by using a sequential chemical bath deposition. Characterizations of the resulting structures by infrared spectroscopy, transmission electron microscopy and photoluminescence measurements are presented. They show that in the case of fresh porous layers, the CdS deposition process is accompanied with some oxidation of the porous material, leading to severe degradation of the luminescence properties. Such degradation is drastically reduced in the case of methyl-grafted layer.
    Materials Science and Engineering B 01/2000; 69:77-80. DOI:10.1016/S0921-5107(99)00271-8 · 2.17 Impact Factor
  • L. Montès · F. Muller · R. Hérino
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    ABSTRACT: Electroplating of II-VI semiconductors like ZnSe into porous silicon can be an efficient and low cost method to fill the porous volume with a transparent and conductive material. With n-type porous layers, ZnSe impregnation is more effective near the sample surface because of reaction rate limitations due to diffusion in the electrolyte. In this paper, it is shown that the deposition of ZnSe into p-type porous silicon can be localized in the lower part of the porous layer if the reduction reaction rate is monitored by limiting the charge carrier supply. This can be done by controlling the power of the laser beam which photo-generates the carriers at the bottom of the pores. Studying the porous layer chemical composition by Auger electron spectroscopy confirms that the deposit is localized at the pore bottom, whereas the changes in the chemical composition of the porous silicon surface are analyzed by infra-red spectroscopy.
    Journal of Porous Materials 01/2000; 7(1):77-80. DOI:10.1023/A:1009611225946 · 1.11 Impact Factor
  • B Gelloz · A Bsiesy · R Herino
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    ABSTRACT: The photoluminescence quenching of lightly doped p-type porous silicon in contact with aqueous acidic electrolytes is investigated under reverse-bias conditions. A complete and reversible quenching of the light emission is observed under infra-red illumination of the samples. This quenching is assigned to the injection into the porous layer of the electrons which are photogenerated in the substrate. The quenching features are studied as a function of the electron concentration in the porous layer, which is varied either by changing the intensity of the light excitation that generates the minority carriers in the silicon bulk or, at a given light intensity, by changing the electrolyte composition. In the latter case, the electron concentration is dependent on the electrochemical reactions which take place at the porous layer surface and which partly consume the injected electrons. It is shown that the amount of injected electrons directly determines the magnitude of the quenching and the associated spectral changes. It is concluded that the assumption of an enhanced charge carrier separation by the electric field as a possible quenching mechanism can be ruled out, and that the experimental results rather support the hypothesis that the quenching involves an Auger recombination process.
    Journal of Luminescence 09/1999; 82(3-82):205-211. DOI:10.1016/S0022-2313(99)00045-9 · 2.72 Impact Factor
  • M. Gros‐Jean · R. Herino · D. Lincot
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    ABSTRACT: The incorporation of cadmium sulfide into porous silicon is investigated with the aim of realizing electrical contacts with the inner surface of the porous material. This is achieved by using a sequential chemical bath deposition method consisiting of the deposition of a few monolayers of cadmium hydroxide in a first solution, and conversion into cadmium sulfide in a second solution containing thioacetamide. This sequence is repeated five times until the pores are completely full. The chemical deposition process is assessed by a detailed analysis of the solution chemistry Characterizations of the deposit by scanning electron microscopy, X‐ray fluorescence, Auger electron spectroscopy, Rutherford back scattering, and X‐ray photoelectron spectroscopy are presented and confirm good pore penetration by CdS, with only a weak concentration gradient from the top to the bottom of the porous layer.
    06/1998; 145(7):2448-2452. DOI:10.1149/1.1838657