Amorphous Semiconductor Superlattices

Abstract

A new class of semiconductor superlattice materials consisting of alternating layers 8-1200-Å thick has been synthesized from semiconductors such as $a-\mathrm{Si}:\mathrm{H}$, $a-\mathrm{Ge}:\mathrm{H}$, $a-\mathrm{Si}{\mathrm{N}}_x:\mathrm{H}$, and $a-{\mathrm{Si}}_{1-x}{\mathrm{C}}_x:\mathrm{H}$. X-ray diffraction, photoconductivity, and photoluminescence measurements indicate that the layers are smooth on an atomic scale, and that the interfaces are essentially defect free. Changes in the optical absorption and photoluminescence as a function of layer thickness in $a-\mathrm{Si}:\mathrm{H}/a-\mathrm{Si}{\mathrm{N}}_x:\mathrm{H}$ superlattices are interpreted as quantum size effects.