Charge-transport interfacial modification enhanced ultraviolet (UV)/near-UV phototransistor with high sensitivity and fast response speed

• C60 phototransistors are fabricated on Si/SiO2 wafer modified by PVA/OTS.
• Ultrahigh photoresponsivity of 234 A/W and external quantum efficiency of 71,825% are achieved utilizing interfacial modification.
• The as-modified devices could obtain lower threshold voltage and higher field-effect mobility.
• C60 deposited on PVA/OTS-modified SiO2 substrate could obtain dense and uniform crystalline grains.
• Photomultiplication effect occurs at the C60/Al interface.

Fullerene (C60) phototransistors were fabricated on Si/SiO2 wafer modified by polyvinyl alcohol/octadecyltrichlorosilane, and their light-induced electric properties were investigated in detail. Operating at room temperature, the as-modified devices offer ultraviolet (UV)/near-UV photoresponse, exhibiting ultrahigh photoresponsivity of 234 A/W, excellent photomultiplication with external quantum efficiency of 71,825%, and the ability to measure high-frequency signals. These parameters are comparable or even superior to commercially available gallium nitride UV photodiodes (GUVA-S12SD). Meanwhile, the as-modified devices could obtain lower threshold voltage and higher field-effect mobility. Experimental and theoretical analyses reasonably explain the excellent photodetection performance, suggesting that charge-transport interfacial modification plays an important role in developing high-performance organic phototransistors.

We report charge-transport interfacial modification of C60-based UV/near-UV phototransistor. The photodetector exhibits high sensitivity and fast response speed due to enhanced charge transport and photomultiplication effect.Figure optionsDownload as PowerPoint slide