The nickel chloride (NiCl2) precursor was placed in an aluminum boat at the upstream and flown by carrier gas Ar at 30 sccm, while Si substrates were put at the downstream.
The substrates were put in a six-well plate and 5 × 105 cells were placed in each well and incubated for 2 h at 37 °C in a 5% CO2 humidified incubator.
Then, cleaned FTO substrates were put into the autoclave, and the hydrothermal process was conducted at 150 °C for 12 h.
The GAZO-deposited glass substrates were put into an inductively coupled plasma system for oxygen plasma treatment to make the surface of the GAZO films hydrophilic.
The metal sources were put in the upstream zone where the temperature was 610°C, while the silicon (100) substrates were put in the downstream zone, the temperature range of which was 750°C ~ 900°C.
The CrCl3 · 6H2O powders were put in the upstream zone of the furnace, where the temperature ranged from 700°C to 800°C, while the silicon (001) substrates were put in the downstream zone with the same temperature range.
The alumina boat was placed in the center of the alumina tube and then the substrates were put into the low region (several center meters) next to the source powder.
