Origin of high carrier mobility and low residual stress in RF superimposed DC sputtered Al doped ZnO thin film for next generation flexible devices

•Investigated origin of high carrier mobility and low residual stress in AZO thin films for next generation flexible devices.•Superimposing RF power onto DC Power controlled energy and flux of incident ions during sputtering process.•Mixed RF/(RF+DC) sputtering process results in better crystallinity and low residual stress.•XPS study shows a variation in defect density in AZO thin film with different RF/(RF+DC) ratios.•The defects finally migrate to grain boundaries and controls the carrier mobility.