The effect of dilute N alloying and Bi surfactant growth on strain relaxation in highly strained InGaAs single quantum well (QWs) was investigated by using high-resolution X-ray diffraction and transmission electron microscopy. Dilute nitride InxGa1-xAs0.99N0.01 quantum wells of varying thickness, constant lattice mismatch 1.7%, were grown by molecular beam epitaxy on oriented GaAs (001) substrates. Some samples were exposed to a flux of Bi surfactant during the growth procedure, which acts to enhance the N incorporation, increase the optical emission, and create smoother interfaces. The quantum wells were observed to relax through the formation of pure edge-type, misfit dislocations aligned with in-plane <100> directions. These were found to be directly associated with degradation in the optical emission, however, 1% N addition, with or without Bi surfactant, did not had a detectable effect on the critical thickness nor the rate of this relaxation mechanism.

Strain Relaxation by <100> Misfit Dislocations in Dilute Nitride InxGa1-xAs1-yNy/GaAs Quantum Wells. E.C.Young, A.N.Koveshnikov, S.Tixier, K.L.Kavanagh, T.Tiedje: Physica Status Solidi A, 2005, 202[15], 2849–57