Photoluminescence quenching effect on porous silicon films for gas sensors application.

Porous silicon (PS) films were investigated by Raman, and photoluminescence (PL) spectroscopies using different laser excitations: 488.0, 514.5, 632.8, and 782.0 nm. The analysis of the first-order and second-order Raman spectra have shown that the band gaps of the PS films are indirect as in the bulk c-Si. The Raman phonon and the PL spectra as well as the spectral distribution of the linear polarisation degree (LPD) of PS layers have shown to be dependent on the laser excitation energy. This dependence cannot be explained within the quantum confinement model. A mechanism for the PL emission in PS layers is presented in which the radiative recombination of electron-hole pairs occurs in localised centres (the Si-O-SiR moieties) at the pore/crystallite interface. These quasi-molecular centres are Jahn-Teller active, i.e. the radiative recombination is a phonon-assisted phenomena. The adsorption of gas molecules on the porous silicon surface was studied throughout photoluminescence quenching effect. The adsorption experiments were performed at 10(-6) bar of pressure using gas molecules of organic solvents. In all these cases, the PL intensity was recovered after gas desorption. The PL quenching effect was explained in the sense of electron transfer mechanism (ET).

[1]  The quenching of porous silicon photoluminescence by gaseous oxygen , 2000 .

[2]  T. D. Harris,et al.  Luminescence and structural study of porous silicon films , 1992 .

[3]  D. L. Fisher,et al.  Energy Transfer Quenching of Porous Si Photoluminescence by Aromatic Molecules , 1995 .

[4]  Michael J. Sailor,et al.  Reversible luminescence quenching of porous silicon by solvents , 1992 .

[5]  Kaplan,et al.  SiHx excitation: An alternate mechanism for porous Si photoluminescence. , 1992, Physical review. B, Condensed matter.

[6]  L. Canham,et al.  Spectroscopic identification of the luminescence mechanism of highly porous silicon , 1993 .

[7]  M. Stutzmann,et al.  Luminescence and optical properties of siloxene , 1993 .

[8]  D. Astruc,et al.  Electron Transfer and Radical Processes in Transition-Metal Chemistry , 1995 .

[9]  Extremely sensitive optical sensing of ethanol using porous silicon , 2000 .

[10]  S. Prokes.  Study of the luminescence mechanism in porous silicon structures , 1993 .

[11]  Changes in the porous silicon structure induced by laser radiation , 2001 .

[12]  Visible Luminescence from Porous Silicon and Siloxene: Recent Results , 1992 .

[13]  V. Petrova-Koch,et al.  The luminescence of porous Si: the case for the surface state mechanism , 1993 .

[14]  Jonathan K. M. Chun,et al.  Proton Gated Emission from Porous Silicon , 1993 .

[15]  L. Canham.  Silicon quantum wire array fabrication by electrochemical and chemical dissolution of wafers , 1990 .

[16]  Volker Lehmann,et al.  Porous silicon formation: A quantum wire effect , 1991 .

[17]  J. Gole,et al.  Origin of porous silicon photoluminescence: Evidence for a surface bound oxyhydride-like emitter , 1997 .

[18]  Stabilization of the photoluminescence from porous silicon: The competition between photoluminescence and dissolution , 1997 .

[19]  L. Canham,et al.  Identification of radiative transitions in highly porous silicon , 1993 .

[20]  Friedman,et al.  Dimensions of luminescent oxidized and porous silicon structures. , 1994, Physical review letters.

[21]  M. Stutzmann,et al.  Triplet excitons in porous silicon and siloxene , 1995 .

[22]  Polarization effects on the Raman and photoluminescence spectra of porous silicon layers , 1999 .

[23]  G. Amato,et al.  A new line shape analysis of Raman emission in porous silicon , 1997 .

[24]  Needs,et al.  Spin-orbit interaction, triplet lifetime, and fine-structure splitting of excitons in highly porous silicon. , 1995, Physical review. B, Condensed matter.

[25]  Wolfgang Benecke,et al.  A novel surface-micromachined capacitive porous silicon humidity sensor , 2000 .

[26]  P. Fauchet,et al.  Conduction and Valence Band Edges of Porous Silicon Determined by Electron Transfer , 1996 .

[27]  Friedman,et al.  Size, shape, and composition of luminescent species in oxidized Si nanocrystals and H-passivated porous Si. , 1995, Physical review. B, Condensed matter.

[28]  S. M. Prokes,et al.  Surface and optical properties of porous silicon , 1996 .

[29]  Michael T. Kelly,et al.  Mechanisms of photoluminescent quenching of oxidized porous silicon applications to chemical sensing , 1998 .

[30]  A. G. Cullis,et al.  The structural and luminescence properties of porous silicon , 1997 .

[31]  W. Theiß,et al.  Optical properties of porous silicon , 1997 .

[32]  P. Klein,et al.  Selective resonant enhancement in the two-phonon Raman spectrum of Si and GaP , 1974 .

[33]  V. Gavrilenko,et al.  Some Perspectives on the Luminescence Mechanism Via Surface-Confined States of Porous Si , 1992 .