Abstract: A field effect transistor including a substrate comprised of a material having a spinel crystal structure and a buffer layer lattice matched to the crystal structure of the substrate comprising gallium aluminum indium arsenide is described. Several types of field effect transistors are possible with the described substrate arrangement, including metal semiconductor field effect transistors, insulating gate field effect transistors, pseudomorphically strained and pseudomorphically strain compensated metal semiconductor field effect transistors, as well as, high electron mobility transistor structures.

Abstract: A thermal energy storage system for storing heat from a solar collector in which latent heat transitions are used to store energy. Ternary systems are disclosed wherein the addition of a third compound gives an additional degree of freedom in controlling crystallization conditions. More specifically, the third compound is used to reduce the amount of incongruent melting found in binary systems of salt hydrates. Preferably, the compounds selected produce a composition whose crystal density approximately equals the liquid density in order to further reduce the segregation of the crystalline phase during the crystallization cycle. Preferred compositions of the storage medium are selected from the hydrates of sodium sulfate, sodium carbonate and dibasic sodium phosphate.