The maximum hole concentration reported from experiment by Kim et al is 1.0 × 10 13 cm -3 , falling within the predicted range and indeed suggesting room for around one order of magnitude improvement. From the present results, it is suggested that M XIII doping, in particular In-doping, could generate an increased hole concentration that would improve the performance of a BaSnO 3 p-n homo-junction, reducing the mismatch between positive and negative carrier densities.