UVB-Sensitive MSM Photodetectors Using Quaternary Gallium-Based Semiconductor Thin Films

IGZO, GZTO, and IGTO thin films were deposited on quartz by radio frequency magnetron sputtering at room temperature and incorporated into Ni/Au metal–semiconductor–metal photodetectors. The comparison identifies a trade-off between ultraviolet responsivity, dark current, and transient recovery. At 280 nm, the responsivities of IGZO, GZTO, and IGTO were approximately 0.054, 0.0019, and 0.080 A/W, respectively, corresponding to calculated external quantum efficiencies of 23.96%, 0.833%, and 34.59%. GZTO exhibited the lowest dark current, whereas IGTO exhibited the highest responsivity and smaller cycle-to-cycle changes in the later transient cycles under the measurement conditions shown. IGZO and GZTO displayed cycle-dependent baseline increases, indicating incomplete recovery within the applied illumination sequences. AFM measurements yielded arithmetic mean roughness values of 1.128, 0.999, and 0.474 nm for IGZO, GZTO, and IGTO, respectively. These results support a comparative assessment of gallium-containing multicomponent oxides for ultraviolet detection without assigning the performance differences to an independently established mobility or defect-density hierarchy.