Si-QD Synthesis for Visible Light Emission, Color Conversion, and Optical Switching

This paper reviews the developing progress on the synthesis of the silicon quantum dots (Si-QDs) via the different methods including electrochemical porous Si, Si ion implantation, and plasma enhanced chemical vapor deposition (PECVD), and exploring their featured applications for light emitting diode (LED), color-converted phosphors, and waveguide switching devices. The characteristic parameters of Si-QD LED via different syntheses are summarized for discussion. At first, the photoluminescence spectra of Si-QD and accompanied defects are analyzed to distinguish from each other. Next, the synthesis of porous Si and the performances of porous Si LED reported from different previous works are compared in detail. Later on, the Si-QD implantation in silicide (SiX) dielectric films developed to solve the instability of porous Si and their electroluminescent performances are also summarized for realizing the effect of host matrix to increase the emission quantum efficiency. As the Si-ion implantation still generates numerous defects in host matrix owing to physical bombardment, the PECVD method has emerged as the main-stream methodology for synthesizing Si-QD in SiX semiconductor or dielectric layer. This method effectively suppresses the structural matrix imperfection so as to enhance the external quantum efficiency of the Si-QD LED. With mature synthesis technology, Si-QD has been comprehensively utilized not only for visible light emission but also for color conversion and optical switching applications in future academia and industry.