Optical characterisation of MOVPE-grown Ga1-xMnxAs semimagnetic semiconductor layers

For the first time, a successful growth of Ga1-xMnxAs layers on (100)GaAs s ubstrates by metal-organic vapour-phase epitaxy is reported. Optical and ma gneto-optical spectroscopy of the E-0, E-1 and E-1 + Delta(1) transitions i s possible due to the high structural quality of the samples. A strong exch ange interaction is found in the Ga1-xMnxAs layers between the magnetic mom ents of manganese and the excitonic states, which exhibits an effective fer romagnetic coupling. The Mn concentrations in the layers can be estimated b y two different and independent optical methods (i) from the Zeeman splitti ng of the E-0 excitons and (ii) from the red-shift of the E-1 transition du e to the p-doping with Mn. (C) 2000 Elsevier Science S.A. All rights reserv ed.