ABSTRACT
This chapter presents the experimental results on photoluminescence (PL) mapping of GaN epilayers with different degrees of order of mosaic structure grown by metal-organic vapour phase epitaxy on sapphire substrates. PL mapping of III-nitride structures and layers is widely applied to reveal an inhomogeneous distribution of optical characteristics. The electron beam induced current (EBIC) mapping measurements were carried out at both room and 220 K temperature on the Schottky barriers in a JSM-840A scanning electron microscope using a Keitley 428 current amplifier. The results of PL and EBIC mapping for GaN epilayers with different degrees of order of mosaic structure showed that the epilayers with the poorly-ordered mosaic structure contained unstable defects. Multifractal analysis allowed these mapping images to be compared quantitatively. Monitoring of the degree of order of mosaic structure is a new approach to improvement of the properties of III-nitride layers.
