OPTICAL-EMISSION RANGE OF STRUCTURES WITH STRAINED INAS QUANTUM DOTS IN GAAS

The photoluminescence of strained InAs quantum dots, produced in situ in a GaAs matrix by molecular-beam epitaxy, is investigated. It is fou nd that the position of the luminescence line shifts to lower energies as the effective thickness of InAs increases from 1.7 to approximatel y 2.7 monolayers and remains virtually constant with further InAs depo sition. Although the InAs deposition dependence of the radiation wavel ength saturates, room-temperature 1.24-mu m emission is achieved in qu antum-well heterostructures deposited on GaAs substrates. The integrat ed photoluminescence intensity increases systematically in the InAs th ickness range 1.7-3 monolayers, after which a section of decreasing in tensity is observed. The dependences obtained are explained in a model according to which the optical emission range of strained quantum dot s is limited on the long-wavelength side by emission from dots with ne arly critical sizes. (C) 1996 American Institute of Physics.