Porous silicon films: Preparation and examination with surface and optical methods

Hardeman, R. W.; Beale, M.I.J.; Gasson, D. B.; Keen, J.M.; Pickering, C.; Robbins, D. J.

doi:10.1016/0039-6028(85)90520-5

Cited by 52 publications

(14 citation statements)

References 9 publications

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“…These studies employed single-crystal Si(100) wafers with a thickness of 400 gm. In agreement with previous studies (24,27), the porous silicon samples produced using the above conditions were bluish-grey in color. The thickness of the porous silicon layer was approximately 2 gm.…”

Section: A Preparation Of Porous Siliconsupporting

confidence: 92%

FTIR Studies of H2O and D2O Decomposition on Porous Silicon Surfaces

Gupta¹,

Dillon²,

Bracker³

et al. 1990

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The decomposition of H 2 0 and D 2 0 on silicon surfaces was studied using transmission Fourier-Transform Infrared (FTIR) spectroscopy. These FHTR studies were performed in-situ in an ultra-high vacuum chamber using high surface area porous silicon samples. The FTIR spectra revealed that H 2 0 (D 2 0) initially dissociates upon adsorption at 300 K to form SiH (SiD) and SiOH (SiOD) surface species, i.e. H 2 0-+ SiH + SiOH. The decomposition of these surface species was then monitored using the Si-H (Si-D) stretch at 2100 cm" 1 (1518 cm' 1), SiO-H (SiO-D) stretch at 3680 cm" 1 (2713 cm" 1) and the Si-O-Si stretch at 900-1100 cm" 1. As the silicon surface was annealed to 650 K, the FTIR spectra revealed that the SiOH surface species progressively decomposed to Si-O-Si species and additional Sill species, i.e. SiOH-* SiH + SiOSi. Above 650 K, the Sill surface species decreased concurrently with the desorption of H 2 from the porous silicon surface. New blue-shifted infrared features in the Si-H stretching region were observed at 2119 cm" 1 , 2176 cm" 1 and 2268 cmr" after annealing above 600 K. Additional infrared studies of partially hydrogen-covered porous silicon surfaces exposed to 02 suggested that these blue-shifted Si-H stretching vibrations were associated with silicon surface atoms backbonded to one, two or three oxygen atoms, respectively.

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Section: A Preparation Of Porous Siliconsupporting

confidence: 92%

FTIR Studies of H2O and D2O Decomposition on Porous Silicon Surfaces

Gupta¹,

Dillon²,

Bracker³

et al. 1990

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“…This result indicates that the GaN films are tetragonally distorted and that a tensile stress has developed in the GaN film. 17 The stress due to the lattice mismatch and the crystal-structure difference between the GaN epitaxial film and the porous Si layer during the growth of the GaN epilayers is relaxed with increase of film thickness by the construction of misfit dislocations. Figure 3 shows the PL spectra for (a) the GaN initial layer/porous Si and (b) the regrowth of the active layer on the GaN initial layer/porous Si.…”

Section: Resultsmentioning

confidence: 99%

Improvement of the crystallinity of GaN epitaxial layers grown on porous Si (100) layers by using a two-step method

2000

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A new approach was used for combining GaN and porous Si with the goal of producing high-quality GaN epitaxial layers for optoelectronic integrated circuit devices based on Si substrates. Reflection high-energy electron diffraction (RHEED), x-ray diffraction (XRD), photoluminescence (PL), and Van der Pauw-Hall effect measurements were performed to investigate the structural, optical, and electrical properties of the GaN epitaxial films grown on porous Si(100) by plasma-assisted molecular-beam epitaxy with a two-step method. The RHEED patterns were streaky with clear Kikuchi lines, which was direct evidence for layer-by-layer two-dimensional growth of GaN epitaxial layers on porous Si layers. The XRD curves showed that the grown layers were GaN(0001) epitaxial films. The results of the XRD and the PL measurements showed that the crystallinities of the GaN epilayers grown on porous Si by using a two-step growth were remarkably improved because the porous Si layer reduced the strains in the GaN epilayers by sharing them with the Si substrates. Hall-effect measurements showed that the mobility of the GaN active layer was higher than that of the GaN initial layer. These results indicate that high-quality GaN epitaxial films grown on porous Si(100) by using two-step growth hold promise for potential applications in new kinds of optoelectronic monolithic and ultralarge integrated circuits.

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“…A current density of 10 mA/cm 2 was applied for 18.9 s to produce the core layer of thickness 2.5 µm and porosity 65 %, while a current density of 109 mA/cm 2 was applied for 13.6 s in the case of the cladding layer with thickness 2.5 µm and porosity 78 %. These porosities correspond to a core and cladding refractive indexes of 1.65 and 1.52, respectively, calculated by the Bruggeman model at a wavelength of 1.5 µm [7]. After the electrochemical etching, the sample was rinsed in ethanol and dried under a stream of N 2 .…”

Section: Methodsmentioning

confidence: 99%

Optical sensing of chemicals by a porous silicon Bragg grating waveguide

Rea

Iodice

Coppola

et al. 2008

Optical Sensors 2008

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A direct laser writing process has been exploited to fabricate a high order Bragg grating on the surface of a porous silicon slab waveguide. The transmission spectrum of the structure, characterized by a pitch of 10 µm, has been investigated by end-fire coupling on exposure to vapor substances of environmental interest. The analyte molecules substitute the air into the silicon pores, due to the capillary condensation phenomenon, and the transmitted spectrum of the grating shifts towards higher wavelengths. The experimental results have been compared with the theoretical calculations obtained by using the transfer matrix method together with the slab waveguide modal calculation.

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Porous silicon films: Preparation and examination with surface and optical methods

Cited by 52 publications

References 9 publications

FTIR Studies of H2O and D2O Decomposition on Porous Silicon Surfaces

FTIR Studies of H2O and D2O Decomposition on Porous Silicon Surfaces

Improvement of the crystallinity of GaN epitaxial layers grown on porous Si (100) layers by using a two-step method

Optical sensing of chemicals by a porous silicon Bragg grating waveguide

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