Improved light reflectance and thermal stability of Ag-based ohmic contacts on p-type GaN with La additive

► We report a new Ag-based p-type GaN contact with La additive. ► A high reflectance and low contact resistivity were obtained from Ag-La contacts. ► The Ag-La contact shows better thermal stability than the Ag contact. ► The addition of La could effectively suppress the Ag agglomeration during annealing.