Conductive atomic force microscopy study of InGaN films grown by hot-wall epitaxy with a mixed (Ga plus In) source

The local morphology and electrical properties of InGaN films grown using a hot-wall epitaxy system coupled with a simple mixed source (metallic galli um and indium) were investigated by means of conductive atomic force micros copy. The photoluminescence (PL) wavelengths of two types of samples grown at different substrate temperatures (685 and 660 degrees C) show different wavelength peaks (400 nm for the former and 420 nm for the latter), even th ough these samples have almost the same In contents as deduced from x-ray d iffraction results. The sample grown at the higher substrate temperature ex hibits a very flat morphology with both a roughness of about 3 nm and a low conductive homogeneous distribution. On the other hand, the sample grown a t the lower substrate temperature shows a rougher topography and inhomogene ous conductive distribution. The longer PL peak and the inhomogeneous condu ctive distribution were attributed to the In fluctuation of the InGaN films . (C) 2000 American Institute of Physics. [S0021-8979(00)00315-7].