Spin polarized electron semiconductor source and apparatus utilizing the same

摘要

There are provided on a substrate a block layer having an electron affinity smaller than that of the substrate, a p-type strained superlattice structure having no lattice relaxation and operating as a generation region of spin polarized electrons and a surface layer for accommodating a bending portion of the energy band. The superlattice structure is formed of a multilayer in which a strained well layer and a barrier layer are alternately laminated plural times. The strained well layer has a lattice constant greater than that of the substrate and a thickness equal to or less than a wavelength of electron wave, and the barrier layer has a conduction band lower in energy than that of the strained well layer and a thickness such that an electron in the conduction band can transmit based on tunnel effect. A difference in energy between the band for heavy holes and the band for light holes is further widened in the valence band of the superlattice structure due to compressive stress in the strained well layer.