Luminescence of porous silicon in a weak confinement regime

Polisski, G.; Heckler, H.; Kovalev, D.; Schwartzkopff, M.; Koch, F.

doi:10.1063/1.122099

Cited by 40 publications

(20 citation statements)

References 18 publications

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“…To monitor the transition to``intrinsicº exciton recombination we have prepared a set of samples with luminescence peak positions starting at the band gap energy (minus energy of TO phonon) of heavily doped silicon ($ 1X05 eV) and shifting in small increments up to 1.4 eV [66] (see Fig. 25).…”

Section: Influence Of the Dopant Atoms On The Emission Properties Of mentioning

confidence: 99%

Optical Properties of Si Nanocrystals

Ковалев¹,

Heckler²,

Polisski³

et al. 1999

phys. stat. sol. (b)

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321

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Section: Influence Of the Dopant Atoms On The Emission Properties Of mentioning

confidence: 99%

Optical Properties of Si Nanocrystals

Ковалев¹,

Heckler²,

Polisski³

et al. 1999

phys. stat. sol. (b)

Self Cite

455

321

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“…They considered that the increase in the E g X energy is due to the quantum confinement in Si nanocrystallites and the increased ⌬R / R intensity as a result of the direct optical transitions. Some reports [51][52][53] also support the possibility of the quasidirect transitions in PSi.…”

Section: -6mentioning

confidence: 91%

Spectroscopic investigation of light-emitting porous silicon photoetched in aqueous HF∕I2 solution

Adachi

2007

Journal of Applied Physics

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The optical properties of porous silicon ͑PSi͒ photoetched in aqueous HF/ I 2 solution are investigated using spectroellipsomety ͑SE͒, electroreflectance ͑ER͒, photovoltage ͑PV͒, photoconductivity ͑PC͒, photoluminescence ͑PL͒, and Fourier transform infrared ͑FTIR͒ spectroscopy. The PSi layers were formed in a HF/ I 2 solution on n-Si substrates under Xe lamp illumination. The SE ͑E͒ and related data show an interference oscillation in the region below E ϳ 3 eV, where the PSi material is nearly transparent. The PV and PC spectra reveal three individual peaks A, B, and C at ϳ1.2, ϳ1.7, and ϳ2.5 eV, respectively, arising from the PSi layer itself. Peak C is also observed in the ER spectrum, together with a broadened E 1 peak at ϳ3.4 eV. Change in the fundamental-absorption-edge nature ͑E g X ͒ from the indirect gap in crystalline silicon to the quasidirect gap in PSi is found in the PV and PC spectra. The PL spectrum shows a broad peak at ϳ2.0 eV͑B͒. Peaks A, B, and C observed in the PSi layer may originate from the nondirect optical transitions at and above the lowest absorption edges E g X ͑A and B͒ and E g L ͑C͒. The quantum-mechanical size effect, i.e., a relaxation of the momentum conservation, makes possible the nondirect or quasidirect transitions at and above E g X and E g L in porous materials. The FTIR data support that the PL emission is due to the surface-sensitive quantum confinement effect.

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“…It has been demonstrated that the photoluminescence ͑PL͒ energy of nc-Si is tunable from the bulk band gap to the visible region by simply controlling the size. [1][2][3][4][5][6] This wide tunability of PL energy indicates that the PL is due to the recombination of excitons confined in zero-dimensional Si quantum dots. The tuning range can be expanded by Si 1Ϫx Ge x alloy formation.…”

Section: Introductionmentioning

confidence: 99%

Electron spin resonance study of defects in Si1−xGex alloy nanocrystals embedded in SiO2 matrices: Mechanism of luminescence quenching

Toshikiyo

Tokunaga

Takeoka

et al. 2001

Journal of Applied Physics

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Dangling bond defects in Si1−xGex alloy nanocrystals (nc-Si1−xGex) as small as 4 nm in diameter embedded in SiO2 thin films were studied by electron spin resonance (ESR), and the effects of the defects on photoluminescence (PL) properties were discussed. It was found that the ESR spectrum is a superposition of signals from Si and Ge dangling bonds at the interfaces between nc-Si1−xGex and SiO2 matrices (Si and Ge Pb centers). As the Ge concentration increased, the signal from the Ge Pb centers increased, while that from the Si Pb centers was nearly independent of Ge concentration. The increase in the number of Ge Pb centers was accompanied by strong quenching of the PL. The observed correlation between the two measurements suggests that the Ge Pb centers act as efficient nonradiative recombination centers for photogenerated carriers, resulting in the quenching of the main PL.

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Luminescence of porous silicon in a weak confinement regime

Abstract: Mechanism of the visible electroluminescence from metal/porous silicon/ n -Si devices

Cited by 40 publications

References 18 publications

Optical Properties of Si Nanocrystals

Optical Properties of Si Nanocrystals

Spectroscopic investigation of light-emitting porous silicon photoetched in aqueous HF∕I2 solution

Electron spin resonance study of defects in Si1−xGex alloy nanocrystals embedded in SiO2 matrices: Mechanism of luminescence quenching

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