This dataset is the result of an investigation into the influence of Si doping on the morphology and luminescence properties of wide-bandgap AlGaN layers. The dataset contains data acquired from three different samples with approximately the same AlN% and a different Si concentration. The data was acquired using an FEI Quanta 250 environmental scanning electron microscope. The secondary electron (SE) and backscattered electron (BSE) images were produced using the manufacturer-supplied software while the cathodoluminescence (CL) hyperspectral images were acquired using a proprietary software package, CHIMP. Figure numbers in the data file descriptions refer to the Applied Physics Letters paper by Kusch et al. (2015) referenced in the related publications section.