Spark-Processed Silicon

What is Spark-Processed Silicon

Directing pulsating plasma discharges to Si modifies macro-and microstructure and generates a substance that strongly photoluminesces in several bands in the visible spectrum. The process of plasma-based discharges is called spark processing. Photoluminescence (PL) peaks were observed in the UV/blue, green, orange/red, and infrared spectral range. The exact center of emission depends on the preparation conditions. The figure below gives an overview by summarizing normalized spectra. The response times are generally fast (picoseconds), and thermal stabilities are high. Microstructure studies reveal a mixture of nanocrystalline Si and amorphous oxidic phases. It should be emphasized that PL with above-band-gap energies was also observed after spark processing of Ge, Sb, Bi, Sn, GaAs, or other materials.

Normalized PL Spectra

Overview of normalized PL spectra from spark-processed Si, prepared (A) under flowing air or in a 1:1 nitrogen/oxygen mixture, (B) in oxygen and subjected to low pressure, (C) under stagnant air conditions or in nitrogen/oxygen atmospheres with volume ratios of >3:1 or <1:3, (D) in oxygen and (E) sp in oxygen and annealed in oxygen at 850 deg C