Session CC - Condensed Matter I.
MIXED session, Friday morning, November 15
Henry Oliver E, Holiday Inn
The ability to fabricate free standing semiconductor quantum wells enables the study of excitons and electrons under the textbook condition of infinite barriers, i. e., the 2-D particle in a box. We have selectively etched compositionally modulated III-V heterostructures to produce quantum wells which are confined on both sides by vacuum. The material is patterned so that the wells are suspended horizontally between vertical supports. This structure is ideal for probing the local properties of solids, e. g., the interaction of quantum confined states with surface or interface states. The inherent high contrast ratio also allows the construction of efficient mirrors for lasers. This is of particular interest in that it allows the fabrication of a Fabry-Perot laser cavity with a linear dimension on the order of the spontaneous emission wavelength of the active medium. The satisfaction of this criterion limits the emission to a single mode and would substantially lower the emission threshold. We have been able to achieve reproducible well widths from 80-200 =C5 with variable spacings from 100 to 2000 =C5 without difficulty.