Below bulk-band-gap photoluminescence at room temperature from heavily P- and B-doped Si nanocrystals

Fujii, Minoru; Toshikiyo, Kimiaki; Takase, Yuji; Yamaguchi, Yasuhiro; Hayashi, Shinji

doi:10.1063/1.1590409

Cited by 131 publications

(147 citation statements)

References 26 publications

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“…This might not prove to be too difficult, once it is recognized as an issue: Recent work on shifting the luminescence spectra of Si nanocrystals indicates that doping with phosphorus or boron may be a simple but effective means of bandgap engineering the peak wavelength of the Si nc PL spectrum [16]. If the Si nc PL can be shifted to the 980-nm (1.2 eV) region, the prospects for efficient optical amplifier and laser operation based on the Er-Si nc material system could be boosted considerably.…”

Section: Discussionmentioning

confidence: 99%

Excited state absorption in the Si nanocluster-Er material system

Loh

Kenyon

2006

IEEE Photon. Technol. Lett.

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Abstract-The issue of Er 3+ excited state absorption in the Si nanocluster-Er material system is highlighted, and an analysis incorporating this interaction presented. We compare our analysis with a prior model of this material, and with regard to previously reported photoluminescence behavior. We show that excited state absorption can explain behavior that has previously been observed, but had not been satisfactorily accounted for.Index Terms-Erbium, optical amplifier, silicon nanocrystal. I. BACKGROUND SILICON nanocluster (nc) sensitized Er-doped silica is a material system that has generated great interest, as it holds considerable promise for practical silicon-based lasers and optical amplifiers [1], [2]. The basic appeal behind the Si nc-sensitized Er system is simple: Using Si nc as the sensitizer to rare-earth ions enables one to take advantage of the large optical absorption cross section of silicon, which is four to five orders of magnitude larger than that of rare-earths in silica. In addition, the broad-band absorption spectrum of Si nc considerably relaxes the wavelength requirements of the pump source, allowing a wider variety of lasers, even light-emitting diodes (LEDs), to be used. Using LEDs instead of laser diodes as pump sources is extremely attractive, as it would reduce pump costs by 10-to 100-fold, extending the scope and accessibility of many more optical applications. There are numerous reports of strong 1550-nm luminescence [3]- [5] in this material system, and even some experimental reports of optical gain [1], [6] in a fabricated waveguide. However, no lasing action has been achieved to date. In spite of considerable work to understand the underlying issues and physics [7]-[9], key optimization parameters and their determining factors remain less than clear. It is the purpose of this work to point out a key interaction-excited state absorption-in this material system; by highlighting and analyzing it here, we believe it will help point the way forward to efficient silicon-based lasers and optical amplifiers. to the metastable state, finally returning to the ground state via optical emission (V).It is generally accepted that the Er ions that are optically active and excitable by the Si nc lie in close proximity (within 1-2 nm) to the nanoclusters. In many reports, the Si nanoclusters, which are themselves luminescent, are found to have their broad photoluminescence (PL) peaks located between 1.5 and 1.6 eV (or a wavelength around 800 nm), which has been attributed either to the silicon-oxygen double bond at the silicon-silica interface [10], [11] or to radiative recombination of confined excitons [12]. Regardless of the cause, spectral hole-burning studies strongly indicate that resonant energy transfer does occur from the Si to the Er in the 800-nm wavelength region [13]. However, we point out in this letter that this energy transfer route may be highly problematic, due to an excited state absorption transition that is known from early work on erbium-doped fiber amplifiers (EDFAs).The b...

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Section: Discussionmentioning

confidence: 99%

Excited state absorption in the Si nanocluster-Er material system

Loh

Kenyon

2006

IEEE Photon. Technol. Lett.

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“…23,24 Doping of Si NCs in a SiO 2 matrix was performed by introducing the dopant in the matrix before NC formation and subsequently inducing dopant incorporation and Si NC formation simultaneously. 14,[25][26][27][28][29][30] This approach indicated that inclusion of electrically active impurities in Si NCs is kinetically possible (e.g. due to the lack of diffusion), and highlighted the corresponding modification of the NC band structure.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic stability of high phosphorus concentration in silicon nanostructures

Perego¹,

Seguini²,

Arduca

et al. 2015

Nanoscale

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Doping of Si nanocrystals (NCs) has been the subject of a strong experimental and theoretical debate for more than a decade. A major difficulty in the understanding of dopant incorporation at the nanoscale is related to the fact that theoretical calculations usually refer to thermodynamic equilibrium conditions, whereas, from the experimental point of view, impurity incorporation is commonly performed during NC formation. This latter circumstance makes impossible to experimentally decouple equilibrium properties from kinetic effects. In this report, we approach the problem by introducing the dopants into the Si NCs, from a spatially separated dopant source. We induce a P diffusion flux to interact with the already-formed and stable Si NCs embedded in SiO 2 , maintaining the system very close to the thermodynamic equilibrium. Combining advanced material synthesis, multi-technique experimental quantification and simulations of diffusion profiles with a rate-equation model, we demonstrate that a high P concentration (above the P solid solubility in bulk Si) within Si NCs embedded in a SiO 2 matrix corresponds to an equilibrium property of the system. Trapping within the Si NCs embedded in a SiO 2 matrix is essentially diffusion limited with no additional energy barrier, whereas de-trapping is prevented by a binding energy of 0.9 eV, in excellent agreement with recent theoretical findings that highlighted the impact of different surface terminations (H-or O-terminated NCs) on the stability of the incorporated P atoms.

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“…Si NCs embedded in SiO 2 are widely investigated for their novel size-dependent electronic and optoelectronic properties [6][7][8][9][10][11][12][13]. In particular, the exploitation of the properties of such systems in real devices demands an accurate control of their doping.…”

Section: Resultsmentioning

confidence: 99%

“…Doping of semiconductor nanostructures has proven to be distinct from the corresponding bulk materials [1][2][3][4][5] and recently great attention has been focused on developing practical methodologies to dope and control the doping properties of Si nanostructures such, as nanoclusters (NCs) [6][7][8][9][10][11][12][13] and nanowires [14][15][16][17], and on developing theoretical approaches to understand these properties [18][19][20][21][22][23]. The control of doping properties of Si nanostructures allows the fabrication of complex nanomaterials characterized by unpreceded electrical and optoelectronic functionalities.…”

Section: Introductionmentioning

confidence: 99%

A Combined Ion Implantation/Nanosecond Laser Irradiation Approach towards Si Nanostructures Doping

Ruffino

Romano

Carria

et al. 2012

Journal of Nanotechnology

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The exploitation of Si nanostructures for electronic and optoelectronic devices depends on their electronic doping. We investigate a methodology for As doping of Si nanostructures taking advantages of ion beam implantation and nanosecond laser irradiation melting dynamics. We illustrate the behaviour of As when it is confined, by the implantation technique, in a SiO 2 /Si/SiO 2 multilayer and its spatial redistribution after annealing processes. As accumulation at the Si/SiO 2 interfaces was observed by Rutherford backscattering spectrometry in agreement with a model that assumes a traps distribution in the Si in the first 2-3 nm above the SiO 2 /Si interfaces. A concentration of 10 14 traps/cm 2 has been evaluated. This result opens perspectives for As doping of Si nanoclusters embedded in SiO 2 since a Si nanocluster of radius 1 nm embedded in SiO 2 should trap 13 As atoms at the interface. In order to promote the As incorporation in the nanoclusters for an effective doping, an approach based on ion implantation and nanosecond laser irradiation was investigated. Si nanoclusters were produced in SiO 2 layer. After As ion implantation and nanosecond laser irradiation, spectroscopic ellipsometry measurements show nanoclusters optical properties consistent with their effective doping.

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Below bulk-band-gap photoluminescence at room temperature from heavily P- and B-doped Si nanocrystals

Cited by 131 publications

References 26 publications

Excited state absorption in the Si nanocluster-Er material system

Excited state absorption in the Si nanocluster-Er material system

Thermodynamic stability of high phosphorus concentration in silicon nanostructures

A Combined Ion Implantation/Nanosecond Laser Irradiation Approach towards Si Nanostructures Doping

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