Tuning of Refractive Indices and Optical Band Gaps in Oxidized Silicon Quantum Dot Solids

This laboratory has initiated compelling research into silicon quantum dot (Si QD) solids in order to utilize their synergetic benefits with quantum dot solids through fabrication of Si QD thin films. The issues of oxidation concerning the Si QD thin films were confirmed using Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The refractive index value of the Si QD thin film at a 30 degrees C curing temperature was 1.61 and 1.45 at 800 degrees C due to complete oxidation of the Si phases. The optical band gap values of 5.49-5.90 eV corresponded to Si phases with diameters between 0.82 and 0.74 nm, dispersed throughout the oxidized Si QD thin films and modeled by Si molecular clusters of approximately 14 silicon atoms. The photoluminescence (PL) energy (2.64-2.61 eV) in the proposed Si QD thin films likely originated from the Si=O bond terminating the Si molecular clusters.