Photoluminescence properties and crystallization of silicon quantum dots in hydrogenated amorphous Si-rich silicon carbide films

Abstract

Silicon quantum dots (QDs) embedded in hydrogenated amorphous Si-rich silicon carbide (α-SiC:H) thin films were realized by plasma-enhanced chemical vapor deposition process and post-annealing. Fluorescence spectroscopy was used to characterize the room-temperature photoluminescence properties. X-ray photoelectron spectroscopy was used to analyze the element compositions and bonding configurations. Ultraviolet visible spectroscopy, Raman scattering, and high-resolution transmission electron microscopy were used to display the microstructural properties. Photoluminescence measurements reveal that there are six emission sub-bands, which behave in different ways. The peak wavelengths of sub-bands P1, P2, P3, and P6 are pinned at about 425.0, 437.3, 465.0, and 591.0 nm, respectively. Other two sub-bands, P4 is red-shifted from 494.6 to 512.4 nm and P5 from 570.2 to 587.8 nm with temperature increasing from 600 to 900 °C. But then are both blue-shifted, P4 to 500.2 nm and P5 to 573.8 nm from 900 to 1200 °C. The X-ray photoelectron spectroscopy analysis shows that the samples are in Si-rich nature, Si-O and Si-N bonds consumed some silicon atoms. The structure characterization displays that a separation between silicon phase and SiC phase happened; amorphous and crystalline silicon QDs synthesized with increasing the annealing temperature. P1, P2, P3, and P6 sub-bands are explained in terms of defect-related emission, while P4 and P5 sub-bands are explained in terms of quantum confinement effect. A correlation between the peak wavelength shift, as well as the integral intensity of the spectrum and crystallization of silicon QDs is supposed. These results help clarify the probable luminescence mechanisms and provide the possibility to optimize the optical properties of silicon QDs in Si-rich α-SiC: H materials.

Boron diffusion in nanocrystalline 3C-SiC

“…Silicon carbide (SiC) is a wide-band gap semiconductor which is widely used for high-power, high-temperature, and high-frequency electronics but requires processing at 1300 C and above. [1][2][3][4][5][6] Nanocrystalline 3C-SiC (nc-3C-SiC) offers an alternative for producing SiC devices at lower temperatures of about 1100 C 4,6-9 and can be synthesized with embedded Si nc that act as quantum dots and exhibit a tunable band gap by annealing Si-rich a-SiC:H. [10][11][12][13] Si nc embedded in SiC are of great interest for solar cells 10,11,[14][15][16][17][18][19][20] and light emission applications 18-20 as they promise a combination of the excellent luminescent properties of Si nc in solution-processed 21,22 or oxide-embedded [23][24][25][26] form with the superior electrical conductivity of doped silicon carbide as compared to SiO 2 or organic ligands. Boron doping is particularly interesting in this metamaterial as it can enhance conductivity, 9 luminescence, and minority carrier lifetime.…”

Silicon nanoparticles synthesized using a microwave method and used as a label‐free fluorescent probe for detection of VB12

“…The two peaks at 531.1 and 532.0 eV in the O 1s spectrum (Fig. S1d) were assigned to Si–O and C=O, respectively . The Si 2p peaks at 101.7 and 102.4 eV in Fig.…”

Phosphorus diffusion in nanocrystalline 3C-SiC

“…The concentration dependence is stronger and begins at higher concentrations for higher drive-in temperatures. Silicon carbide (SiC) has many applications in highpower, high-temperature, and high-frequency electronics 1-3 due to its thermal and chemical stability and high band gap but requires processing above 1300 C. 4-6 Nanocrystalline 3C-SiC (nc-3C-SiC) can be processed at lower temperatures around 1100 C, 4,6-9 and can be produced with embedded Si quantum dots (QDs) by annealing Si-rich a-SiC:H. [10][11][12][13] Si QDs embedded in SiC promise a combination of the excellent luminescent properties of oxide-embedded QDs 14-17 with the superior electrical conductivity of doped SiC, making it an interesting active material for light emission [18][19][20] and photovoltaics. 12,21-24 Nanocrystalline 3C-SiC also has other applications in thin film solar cells 25,26 and MEMS.…”