Mid-Infrared Photoconductivity in Self-Assembled InAs Quantum Dots
Abstract
Observations of mid-infrared photoconductivity in self-assembled InAs quantum dots are observed. The dots, which self-assemble into squat pyramidal shapes approximately 10 nm on a side and 2-3 nm high, are grown using standard molecular beam epitaxy techniques and coherently strained in a matrix of Al_0.3Ga_0.7As which has been grown on a GaAs substrate. Using a variety of cladding structures and dots doped with electrons, normal incidence photoconductivity has been measured at a range of wavelengths in the mid-infrared. Observations at different sample temperatures and applied bias allows discrimination and explanation of different tranistion processes, including excitation of carriers from the ground state of the dots into both excited states and the continuum. Photoluminescence and electroluminescence experiments are in good agreement with the observed optical transitions. The large optical response of these quantum dot samples suggests possible future use as novel mid-infrared detectors. Infrared photoconductivity is investigated for several different dot structures, and the possibility of further optimization of self-assembled quantum dots for both mid-infrared detection and emission will be discussed.
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 1997
- Bibcode:
- 1997APS..MAR.B1316B