Experimental evidence of α → β phase transformation in SiC quantum dots and their size-dependent luminescence

Abstract

Effect of elemental composition and size on electron confinement in self-assembled SiC quantum dots: A combinatorial approach

Optical properties of mesoporous 4H-SiC prepared by anodic electrochemical etching

“…In our study, the XRD provides a better estimation of the interpore spacing. The XRD data also suggest that the sonication process did not result in a phase change in the 4H polytype as has been reported for 4H and 6H-SiC based QDs after ultrasonication where the interplanar spacings of 0.217 nm for 3C ð20 20Þ planes 34 and 0.195 nm for 3C ð21 30Þ planes 35 were found.…”

“…The red-shifting in PL peaks with increasing excitation wavelengths is another means of confirming the existence of the quantum size effects. 27,31,35,75,76 Figure 7(a) shows the PL spectra at room temperature for bulk 4H-SiC and S-Por-SiC in ethanol for a range of excitation wavelengths. S-Por-SiC exhibited enhanced PL emission with an intensity approximately 100 times greater than the bulk.…”

“…Several experimental observations are not fully described involving 3C, 4H, and 6H-SiC polytypes, which unexpectedly show similar PL despite the different crystal structure and bandgaps. This has been claimed to be related to phase transformation from 4H or 6H into 3C during the ultrasonication process 34,35 based on XRD and QD lattice spacing measurements. However, the potential contributions from surface defects and surface terminations, which may give rise to the similar PL characteristics, remain inconclusive.…”

High rate fabrication of room temperature red photoluminescent SiC nanocrystals

“…[1][2][3][4][5] However, the indirect band gap of bulk SiC material leads to its weak emission property, which has hampered its application in optical devices. [9][10][11][12][13][14] This PL property can be attributed to the formation of a direct band gap and quantum confinement effect in SiC nanocrystals. 7,8 SiC nanocrystals are found to have several excellent properties such as photoluminescence (PL) at room temperature.…”

Dominant luminescence is not due to quantum confinement in molecular-sized silicon carbide nanocrystals

“…In the case of molecular-sized SiC NCs surface related luminescence is dominant 34,46 . SiC NCs made by electroless wet chemical etching contain a large number of oxidized surface groups because of the applied strong acids.…”