(AlGa)As composition profile analysis of trenches overgrown with MOVPE

In this paper we present an examination of (Al0.3Ga0.7)As layers grown by M OVPE at different temperatures over trenches etched into (100) GaAs in [0 1 1] direction. On the sidewalls of the trenches, the Al content is reduced compared to planar regions. High-resolution cathodoluminescence (CL) shows that the region with lower Al content is homogeneous along the sidewalls an d that the Al content changes abruptly at the change of growth facets, To g et information on the growth mechanism GaAs quantum wells are embedded with in the (AlGa)As, Their CL emission wavelength is different for the sidewall s and planar regions indicating different thicknesses and thus growth rates . The GaAs growth rates are compared with the (AlGa)As growth rates and the change in Al content on the sidewalls, The results lead to a contradiction , Therefore, the growth of (AlGa)As over trenches cannot be treated as the sum of its binary components. (C) 2001 Published by Elsevier Science B.V.