The synthesis of dopant-controlled Au@AZO NPs was achieved by first synthesizing Au@Zn(OH)2 core@shell NPs in the absence of any Al 3+ doping, centrifuging the product and redispersing it in a pH-neutral aqueous solution of aluminum nitrate (Al(NO3)3). The Au@Zn(OH)2 core@shell NPs are left infusing in the Al 3+ solution for 30 minutes before deposition on a silicon substrate and annealing. This process is illustrated in Procedure 2 in Scheme 1. Using a non-neutralized aluminum nitrate solution results in compromised particle morphology and uniformity (Figure SI.5).