This invention is directed to a method and apparatus for growing a multi-component single crystal boules that provides high quality and growth rate by growing the crystal from a multi-component melt, such as a ternary, quaternary or higher order melt. In the past, only binary compounds such as GaAs) could be commercially produced by directional solidification from melts, while compounds with more than two components resulted in a high density of defects.
The subject invention relates to a method for making ternary and quaternary semiconductor materials. These materials are currently produced in the form of thin layers by non-equilibrium growth techniques (from diluted solutions and vapor phase) on binary substrates using buffer layers to relieve misfit related stresses at the epilayer-substrate interface. One disadvantage of epitaxial technology is its high cost. In addition, the buffer layer technology is not optimized for all systems, and often devices exhibit large leakage currents due to poor interfacial regions.
Rensselaer researchers have developed a new class of phosphors that have narrow spectral linewidths suitable for high-efficiency, white light LED fabrication for lighting and display applications. These phosphors can be efficiently excited by near UV and blue LEDs such as in 400 nm LEDs and can provide emission in green, yellow, amber and red wavelengths. Commercial phosphor-converted white LEDs lack narrow-emitting red phosphors that are effectively excited by blue or near ultraviolet LEDs.
This technology relates to a full spectrum broad wavelength emission white light source fabricated using a graded composition optically clear substrate that enables high efficiency, high flux, narrow or wide spectral width, large area, low cost LEDs with peak emission wavelength in the range of visible wavelength range from 400-750 nm.
This technology relates to a wireless radio communications scheme that minimizes interferences between different channels and increases high bandwidth data communication. Furthermore, this modulation scheme is easy to implement with simple low cost electronic systems. Possible applications for this technology include: optical communication, energy efficient illumination, optical signal processing, smart shower heads, fertilizer dispensers, hydroponics systems, smart automobile brakes, adaptive lighting systems, medical diagnostic systems, etc.
Semiconductor nanoparticles (also called quantum dots or nanocrystals) are generally used a lasing medium in a laser, as fluorescent tags in biological testing methods, and as electronics devices. However, these nanoparticles traditionally have high production costs and the methods used for synthesis are extremely toxic at high temperatures, posing safety risks during mass production. Additionally, it has been difficult to form nanoparticles of uniform size. This invention is directed to semiconductor nanoparticles having an elementally passivated surface.