Laser Spectroscopy of Quantum Well and Superlattice Structures
Abstract
The potential for tailoring band structures of semiconductors with specific properties using molecular beam epitaxy (MBE) and metallorganic chemical vapour deposition (MOCVD) has considerable significance for future electronic and optoelectronic devices. These techniques permit the growth of structure with alternating layers of two semiconductors on top of each other which have band structures that alternate with characteristic peridocity (Fig. 1b) giving a one-dimensional Kronig-Penney structure. Superlattices are grown with well widths ranging from 1-50nm with rather thicker barriers. Electrons and holes are confined in the potential wells in the conduction and valence bands respectively. The transition rates of these excitonic luminescence processes should be given by the inverse of the radiative lifetime, tau sub R, leading to a homogeneous linewidth Delta omega = 1/tau sub R. At low temperature the exciton linewidth for a typical 5.0nm well in GaAs is about 100 times larger than in bulk material, which is already inhomogeneously broadened by the effects of strain. Obviously the exciton luminescence line experiences an additional inhomogeneous broadening which dominates the experimental linewidth.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 04, 1990
- Accession Number
- ADA236232
Entities
People
- B. Henderson
Organizations
- University of Strathclyde