Band gap engineering of amorphous silicon quantum dots for light-emitting diodes

Park, Nae-Man; Kim, Taesoo; Park, Seong-Ju

doi:10.1063/1.1367277

Cited by 370 publications

(248 citation statements)

References 10 publications

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“…It is well known that the silicon excess in silicon-rich dielectrics agglomerates forming Si-nps after high temperature annealing, resulting in a redshift of the PL band due to the quantum coninement efects [53][54][55][56][57]. However, contrary to this assumption, in this work, the PL blueshifts after the annealing, as shown in Figure 4(b).…”

Section: Silicon-rich Nitride (Srn) Ilmcontrasting

confidence: 53%

Luminescent Devices Based on Silicon-Rich Dielectric Materials

Cabañas-Tay¹,

Palacios-Huerta²,

Aceves-Mijares³

et al. 2016

Luminescence - An Outlook on the Phenomena and Their Applications

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Luminescent silicon-rich dielectric materials have been under intensive research due to their potential applications in optoelectronic devices. Silicon-rich nitride (SRN) and silicon-rich oxide (SRO) ilms have been mostly studied because of their high luminescence and compatibility with the silicon-based technology. In this chapter, the luminescent characteristics of SRN and SRO ilms deposited by low-pressure chemical vapor deposition are reviewed and discussed. SRN and SRO ilms, which exhibit the strongest photoluminescence (PL), were chosen to analyze their electrical and electroluminescent (EL) properties, including SRN/SRO bilayers. Light emiting capacitors (LECs) were fabricated with the SRN, SRO, and SRN/SRO ilms as the dielectric layer. SRN-LECs emit broad EL spectra where the maximum emission peak blueshifts when the polarity is changed. On the other hand, SRO-LECs with low silicon content (~39 at.%) exhibit a resistive switching (RS) behavior from a high conduction state to a low conduction state, which produce a long spectrum blueshift (~227 nm) between the EL and PL emission. When the silicon content increases, red emission is observed at both EL and PL spectra. The RS behavior is also observed in all SRN/SRO-LECs enhancing an intense ultraviolet EL. The carrier transport in all LECs is analyzed to understand their EL mechanism.

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Section: Silicon-rich Nitride (Srn) Ilmcontrasting

confidence: 53%

Luminescent Devices Based on Silicon-Rich Dielectric Materials

Cabañas-Tay¹,

Palacios-Huerta²,

Aceves-Mijares³

et al. 2016

Luminescence - An Outlook on the Phenomena and Their Applications

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“…The generation of the QD inside the a-SiO 2 matrix allows the formation of Si-O-Si bridge bonds at the Si/SiO 2 interface, and the reduction of the embedded system energy gap in all the systems, as shown by previous theoretical studies, 16,64 and in accordance with photoluminescence measurements where the energy gap for QDs around 2.5 nm in diameter was determined to be 1.9 eV for amorphous QDs 65 and 2.7 eV for crystalline ones. 66 Similarly to the crystalline case, HOMO and LUMO states of amorphous systems are localized at the surface of the QD and inside it, respectively.…”

Section: Sio 2 Matrices and Siqdssupporting

confidence: 53%

Silicon quantum dots embedded in a SiO2matrix: From structural study to carrier transport properties

et al. 2013

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We study the details of electronic transport related to the atomistic structure of silicon quantum dots embedded in a silicon dioxide matrix using ab initio calculations of the density of states. Several structural and composition features of quantum dots (QDs), such as diameter and amorphization level, are studied and correlated with transport under transfer Hamiltonian formalism. The current is strongly dependent on the QD density of states and on the conduction gap, both dependent on the dot diameter. In particular, as size increases, the available states inside the QD increase, while the QD band gap decreases due to relaxation of quantum confinement. Both effects contribute to increasing the current with the dot size. Besides, valence band offset between the band edges of the QD and the silica, and conduction band offset in a minor grade, increases with the QD diameter up to the theoretical value corresponding to planar heterostructures, thus decreasing the tunneling transmission probability and hence the total current. We discuss the influence of these parameters on electron and hole transport, evidencing a correlation between the electron (hole) barrier value and the electron (hole) current, and obtaining a general enhancement of the electron (hole) transport for larger (smaller) QD. Finally, we show that crystalline and amorphous structures exhibit enhanced probability of hole and electron current, respectively.

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“…2(a)]. A monotonous increase of EL is observed, while the quantum-size effect is known to be significant only when the silicon layer thickness is below 10 nm [13], [14]. The electroluminescence is inversely proportional to the access region thickness in the full range.…”

Section: Resultsmentioning

confidence: 84%

Strong Efficiency Improvement of SOI-LEDs Through Carrier Confinement

Hoang¹,

LeMinh²,

Holleman³

et al. 2007

IEEE Electron Device Lett.

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Abstract-Contemporary silicon light-emitting diodes in silicon-on-insulator (SOI) technology suffer from poor efficiency compared to their bulk-silicon counterparts. In this letter, we present a new device structure where the carrier injection takes place through silicon slabs of only a few nanometer thick. Its external quantum efficiency of 1.4 · 10 −4 at room temperature, with a spectrum peaking at 1130 nm, is almost two orders higher than reported thus far on SOI. The structure diminishes the dominant role of nonradiative recombination at the n + and p + contacts, by confining the injected carriers in an SOI peninsula. With this approach, a compact infrared light source can be fabricated using standard semiconductor processing steps.

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Band gap engineering of amorphous silicon quantum dots for light-emitting diodes

Cited by 370 publications

References 10 publications

Luminescent Devices Based on Silicon-Rich Dielectric Materials

Luminescent Devices Based on Silicon-Rich Dielectric Materials

Silicon quantum dots embedded in a SiO2matrix: From structural study to carrier transport properties

Strong Efficiency Improvement of SOI-LEDs Through Carrier Confinement

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