Graded-size Si quantum dot ensembles for efficient light-emitting diodes

Anopchenko, Aleksei; Marconi, A.; Wang, M.; Pucker, G.; Bellutti, P.; Pavesi, L.

doi:10.1063/1.3658625

Cited by 43 publications

(29 citation statements)

References 20 publications

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“…Figure 1 b-d illustrate energy band diagrams of un-, forward-, and reverse-biased graphene/SQDs:SiO 2 MLs/n-Si junction under illumination, respectively (see Figure S3, Supporting Information for the device under dark condition). [21][22][23] The local current minimum under small positive bias, indicating the tunneling behavior, [ 24 ] is observed at temperatures ≤100 K. ( Figure S4, Supporting Information). [ 19,20 ] Figure 1 e shows dark I -V curves for various p-type doping concentrations ( n D ) of graphene at a fi xed d of 2.8 nm.…”

Section: Doi: 101002/adma201500040mentioning

confidence: 99%

Graphene/Si‐Quantum‐Dot Heterojunction Diodes Showing High Photosensitivity Compatible with Quantum Confinement Effect

Shin

Kim

et al. 2015

Advanced Materials

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Graphene/Si quantum dot (QD) heterojunction diodes are reported for the first time. The photoresponse, very sensitive to variations in the size of the QDs as well as in the doping concentration of graphene and consistent with the quantum-confinement effect, is remarkably enhanced in the near-ultraviolet range compared to commercially available bulk-Si photodetectors. The photoresponse proves to be dominated by the carriertunneling mechanism.

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Section: Doi: 101002/adma201500040mentioning

confidence: 99%

Graphene/Si‐Quantum‐Dot Heterojunction Diodes Showing High Photosensitivity Compatible with Quantum Confinement Effect

Shin

Kim

et al. 2015

Advanced Materials

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“…These latter results will undoubtedly have an impact on the previously mentioned applications of Si-ncs, notably on photovoltaics and electrically-driven devices such as memristors or LEDs. This may also have some repercussions on the design and nano-engineering on multiple monolayers of Sincs in SiO 2 [35], photoluminescence down shifter for solar cells [36] or graded-size Si quantum dots [37]. We chose here to investigate further this thickness-dependence on the sensitization of Er 3+ ions in such layers, which may lead to more insights on the excitation mechanism of these latter.…”

Section: Device Processing and Electrical Characteristicsmentioning

confidence: 99%

Structural factors impacting carrier transport and electroluminescence from Si nanocluster-sensitized Er ions

Cueff¹,

Labbé²,

Jambois³

et al. 2012

Opt. Express

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Abstract:We present an analysis of factors influencing carrier transport and electroluminescence (EL) at 1.5 µm from erbium-doped silicon-rich silica (SiO x ) layers. The effects of both the active layer thickness and the Siexcess content on the electrical excitation of erbium are studied. We demonstrate that when the thickness is decreased from a few hundred to tens of nanometers the conductivity is greatly enhanced. Carrier transport is well described in all cases by a Poole-Frenkel mechanism, while the thickness-dependent current density suggests an evolution of both density and distribution of trapping states induced by Si nanoinclusions. We ascribe this observation to stress-induced effects prevailing in thin films, which inhibit the agglomeration of Si atoms, resulting in a high density of sub-nm Si inclusions that induce traps much shallower than those generated by Si nanoclusters (Si-ncs) formed in thicker films. There is no direct correlation between high conductivity and optimized EL intensity at 1.5 µm. Our results suggest that the main excitation mechanism governing the EL signal is impact excitation, which gradually becomes more efficient as film thickness increases, thanks to the increased segregation of Si-ncs, which in turn allows more efficient injection of hot electrons into the oxide matrix. Optimization of the EL signal is thus found to be a compromise between conductivity and both number and degree of segregation of Si-ncs, all of which are governed by a combination of excess Si content and sample thickness. This material study has strong implications for many electricallydriven devices using Si-ncs or Si-excess mediated EL. USSR 5, 685-687 (1938). ©2012 Optical Society of America

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“…The active layer of Si-NCs LED is a graded-size multilayer with specifications described in Anopchenko et al work [14]. The electroluminescence (EL) as a function of current is presented in Fig.…”

Section: B II Experimentalmentioning

confidence: 99%

Quantum random number generator based on silicon nanocrystals LED

et al. 2015

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We present a post-processing free quantum random number generator (QRNG) based on silicon nanocrystals (Si-NCs) LEDs as a source of randomness. The relatively simple setup for data extraction, a negligible bias measured from the datasets and applying no post-processing operations to the raw data are the main advantages of this QRNG . The obtained bit sequences pass all the NIST tests and the highest bit-rate achieved is 0.6 Mbps. A. IntroductionRandom numbers are highly significant in many applications including Monte Carlo simulations [1, 2] and particularly cryptography [3,4] where producing unpredictable results is absolutely vital to guarantee complete security of data transmission. In several situations random numbers are obtained through pseudo random number generators (PRNG) which are deterministic algorithms able to output long sequences of bits at high bit-rates. However, their unpredictability is not totally assured since when the seed (initial value) is revealed, all the bits in the sequence will consequently be constructed. Contrary to pseudo random numbers, truly random numbers essentially need to be generated through physical nondeterministic processes [3]. These processes include a wide range of physical phenomena fundamentally based on quantum physics. The main disadvantage of physical RNGs is the difficulty of obtaining statistically good bit sequences and usually deterministic functions called post-processing are applied to the output data.Inherent randomness and indeterminacy provided by quantum physics can be exploited advantageously to generate random numbers. Quantum dots [5,6], single photon avalanche photodiode (SPAD) [7], light emitting devices (LEDs) [8,9], laser [10, 11], chaotic laser [12] , and atmospheric turbulence [13] have been employed as sources of entropy to produce random numbers. In this paper we present a quantum RNG (QRNG) based on silicon nanocrystals (SiNCs) LEDs, able to produce statistically good bit sequences using a simple experimental setup for data extraction. Si-NCs LEDs have several advantages such as CMOS compatibility,

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Graded-size Si quantum dot ensembles for efficient light-emitting diodes

Abstract: Articles you may be interested inNanocrystalline-Si-dot multi-layers fabrication by chemical vapor deposition with H-plasma surface treatment and evaluation of structure and quantum confinement effects AIP Advances 4, 017133 (2014);

Cited by 43 publications

References 20 publications

Graphene/Si‐Quantum‐Dot Heterojunction Diodes Showing High Photosensitivity Compatible with Quantum Confinement Effect

Graphene/Si‐Quantum‐Dot Heterojunction Diodes Showing High Photosensitivity Compatible with Quantum Confinement Effect

Structural factors impacting carrier transport and electroluminescence from Si nanocluster-sensitized Er ions

Quantum random number generator based on silicon nanocrystals LED

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