Low-Temperature-Crystallized Ga 2 O 3 Thin Films and Their TFT-Type Solar-Blind Photodetectors.

Crystalline Ga 2 O 3 (c-Ga 2 O 3 ) is a promising candidate for next-generation solar-blind photodetectors (SBPDs) but is suffering from high processing temperatures. Herein, seed-induced engineering is proposed via adopting Zn as an induced metal for crystallizing Ga 2 O 3 , lowering the processing temperature by 200 °C. After annealing, the Zn/Ga 2 O 3 consists of an inner Ga 2 O 3 layer of a monoclinic crystalline phase, top ZnO crystals coming from Zn oxidation, and a thin corundum Ga 2 O 3 layer between them, which implies a "seed-induced" crystallization mechanism besides the nonequilibrium chaotic state caused by the traditional electron transfer one. As a result, the tailored c-Ga 2 O 3 thin-film transistor-type SBPD with enhanced packing density and finite oxygen deficiency demonstrates a satisfactory responsivity of 8.6 A/W and also an ultrahigh UVC/visible rejection ratio ( R 254 / R 450 ) of 2 × 10 5 . The seed-induced engineering forecasts its potential application in crystalline Ga 2 O 3 SBPDs under a relatively low processing temperature.