Yellow electroluminescence (EL) of a 20-pair Si-rich SiN x /SiO x superlattice is demonstrated by plasma-enhanced chemical vapor deposition (PECVD) and annealing process. After annealing at 900 C for 30 min, two photoluminescence (PL) peaks at 480 and 570 nm are observed to blue-shift the PL wavelength, and the corresponding peak intensity is enhanced due to the self-aggregation of Si quantum dots (QDs). When increasing the annealing temperature to 1050 C, the PL peaks caused by the aggregated Si-QDs in SiN x and SiO x layers red-shift to 500 and 600 nm, thereby shifting the PL peak wavelength to 520 nm. Such a wavelength red-shifting phenomenon is mainly attributed to the formation of large Si-QDs due to the Ostwald ripening effect. The turn-on voltage and the V -I slope of the ITO/SiN x /SiO x /p-Si/Al LED device are 200 V and 15.5 kV/mA with FowlerNordheim (FN) tunneling assistant carrier transport under an effective barrier height of 1.3 eV. Maximum output-power-current slope of 0.2 W/A at power conversion efficiency of 10 À6 is detected.

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Broadband orange and white light band solid-state phosphor using stoichiometry detuned a-SixC1−x films with buried SiC and Si nanocrystals are demonstrated for white lighting applications.

The co-precipitation of Si and SiC quantum dots (QDs) in Si-rich silicon carbide (Si-rich SiC) films with n-type and p-type dopants is preliminarily demonstrated with low-temperature plasma enhanced chemical vapor deposition and high-temperature annealing. With specific hydrogen-free recipe of argon diluted silane (SiH4) and pure methane (CH4), the composition ratio x of Si-rich SixC1-x film can be varied from 0.74 to 0.67 by tuning the flow rate of g = [CH4]/([CH4]+[SiH4]) from 40% to 60%. Both SiC-QDs and Si-QDs can only be precipitated by annealing the Si-rich Si0.69C0.31 grown with g = 50% at 1050°C. The Si0.69C0.31 transfers into a nano-crystallized matrix with buried SiC-QDs and Si-QDs at diameters of 2.5 nm and 4.5 nm, respectively. The co-precipitated SiC-QDs and Si-QDs in Si-rich Si0.69C0.31 shrink the linewidth of c-Si related Raman scattering peak at 520 cm−1 from 87 cm−1 to 42 cm−1, and up-shift the Si-C transverse optical (TO) and longitudinal optic (LO) mode related Raman scattering peaks to 796 cm−1 and 970 cm−1, respectively. Decreasing the flow rate from g = 60% to g = 50% improves the conductivity of Si-rich SixC1-x film by more than one order of magnitude. At optimized recipe of g = 50%, the resistivities of p-type and n-type SixC1-x films are reduced to 2 × 101 Ω-cm and 3.1 × 10−1 Ω-cm, respectively.

An amorphous Si-rich SiC film with nearly warm white-light photoluminescence is synthesized to serve as a solid-state phosphorous material for white-lighting applications.

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