| 摘要 |
PURPOSE:To realize physical properties equivalent to those expected in a quaternary mix crystal, by laminating a multiplicity of semiconductor monocrystalline thin films of two or more different binary or ternary compounds whose lattice constants are different from each other by a specific range, alternately at a specific repeated cycle, and by using materials whose thickness ratio is set such that the average composition approximately corresponds to the composition of a given quaternary mix crystal. CONSTITUTION:A multiplicity of semiconductor monocrystalline thin films of two or more different binary or ternary compounds whose lattice constants are different from each other by 5% or less are layered alternately at a repeating cycle. The repeating cycle is set so as to be less than the de Broglie wavelength of electrons in the semiconductors, and a thickness ratio is set such that the average composition approximately corresponds to the composition of a givenquaternary mix crystal. When a thin film superlattice of GaSb and InAs are used instead of In1-xGaxAs1-ySby, for example, the difference in bulk lattice constant between the two is only ¦a(InAs)-a(GaSb)¦/a(GaSb)= 0.6%. Therefore, a stable superlattice can be produced with a slight distortion to each other. Physical properties equivalent to those of the quaternary mix crystal having a composition represented by the line D in the drawing can be realized by appropriately setting a thickness ratio of the layers in such a superlattice. |
