Semiconductor device including ordered layers.

摘要

Semiconductor devices are described including a structure of alternating first and second layers of Group-IV materials which together form an ordered composite structure having a crystallographic unit cell which differs from the unit cells of both the first and second layer materials. Structures in which both first and second layers are not more than 8 atomic monolayers thick have properties (such as, e.g., electronic or optical properties) which are significantly different from those of previously known Group-IV semiconductor materials and structures. As a result, structures of the invention give rise to novel device applications. In the case of germanium and silicon layer materials, the number of monolayers in first and second layers strongly affects electroabsorption properties. A structure of alternating first layers of 4 atomic monolayers Ge and second layers of 4 atomic monolayers Si is of particular interest for photodetector use on account of strong optical absorption at wavelengths near 1.6 micrometer.