Generation of optically active states in a-SiNx by thermal treatment

Ko, Changhun; Han, Mei; Shin, Hyun‐Joon

doi:10.1016/j.jlumin.2011.03.020

Cited by 2 publications

(1 citation statement)

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“…Many groups attributed the photoluminescence (PL) peak blueshift with decreasing NC size to quantum confined excitons in the nitride-embedded Si NCs or amorphous silicon quantum dots (Si QDs). [9][10][11][12][13][14] Alternatively, radiative defects [15][16][17][18] or band tail luminescence 11,16,19 was suggested to explain the PL. In this work, we present evidence that PL emission from quantum confined excitons in nitride-embedded Si NCs is very unlikely due to the quenching effect of abundant non-radiative defects and a possible loss of confinement potential due to extensive tail states in Si 3 N 4 .…”

Section: Introductionmentioning

confidence: 99%

Absence of quantum confinement effects in the photoluminescence of Si3N4–embedded Si nanocrystals

Hiller¹,

Zelenina²,

Gutsch³

et al. 2014

Journal of Applied Physics

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Superlattices of Si-rich silicon nitride and Si 3 N 4 are prepared by plasma-enhanced chemical vapor deposition and, subsequently, annealed at 1150 C to form size-controlled Si nanocrystals (Si NCs) embedded in amorphous Si 3 N 4 . Despite well defined structural properties, photoluminescence spectroscopy (PL) reveals inconsistencies with the typically applied model of quantum confined excitons in nitride-embedded Si NCs. Time-resolved PL measurements demonstrate 10 5 times faster time-constants than typical for the indirect band structure of Si NCs. Furthermore, a pure Si 3 N 4 reference sample exhibits a similar PL peak as the Si NC samples. The origin of this luminescence is discussed in detail on the basis of radiative defects and Si 3 N 4 band tail states in combination with optical absorption measurements. The apparent absence of PL from the Si NCs is explained conclusively using electron spin resonance data from the Si/Si 3 N 4 interface defect literature. In addition, the role of Si 3 N 4 valence band tail states as potential hole traps is discussed. Most strikingly, the PL peak blueshift with decreasing NC size, which is often observed in literature and typically attributed to quantum confinement (QC), is identified as optical artifact by transfer matrix method simulations of the PL spectra. Finally, criteria for a critical examination of a potential QC-related origin of the PL from Si 3 N 4 -embedded Si NCs are suggested. V C 2014 AIP Publishing LLC. [http://dx.

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