Characteristics of InAs "dots-in-a-graded-well"

A number of studies have now established that the use of (In,Ga)As quantum-dot nanostructures in active regions of infrared detectors and lasers has desirable effects on some key characteristics of these devices. Intersublevel quantum-dot infrared detectors, for example, can detect normal-incidence light, unlike quantum-well detectors which operate under the similar principles. Quantum-dot lasers with a range of desirable properties such as ultra-low threshold current densities, low sensitivity to temperature variations, and long wavelength (1.3 /spl mu/m) emission have been demonstrated. In lasers, however, the quantum-dot media do not often have sufficient gain for the structures to lase at the ground state. This paper explores a structure that could potentially be used to enhance the gain in quantum-dot active media.