title: Photosensitive organic field effect transistors: the influence of ZnPc morphology and bilayer dielectrics for achieving a low operating voltage and low bias stress effect.
abstract: Photosensitive-organic field effect transistors (PS-OFETs) based on a morphology controlled zinc phthalocyanine (ZnPc) layer, with an inorganic-organic bilayer gate dielectric system, fabricated on a glass substrate showed remarkable efficiency as light sensors at various incident optical powers. The indium tin oxide (ITO) and Si/SiO2free low-cost OFET devices show low bias stress and a reduced operating voltage with aluminum oxide and poly(methyl methacrylate) (Al2O3/PMMA) as bilayer gate dielectrics and copper (Cu) as a top contact. They exhibit excellent p-channel behavior with a remarkable photo-responsivity of 2679.40 A W-1and a photo-ON/OFF current ratio of 933.56 with a very low operating voltage (0 to -8 V), which have not been observed previously. The bias stress effect of the device was investigated under both light and dark conditions in a vacuum. It was observed that the effect of the stress is extremely small in the presence of light (a decay of IDSof ∼ 20% after 30 min) compared to the dark, with a characteristic carrier relaxation time τ' ∼ 104s. This device with high electrical stability under ambient conditions and a low threshold voltage under constant electrical bias stress is expected to have potential applications in optoelectronic devices and energy efficient sensors.
authors.affiliation: Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati-781039, India and Centre for Nanotechnology, Indian Institute of Technology Guwahati, Guwahati-781039, India. pki@iitg.ernet.in.
authors.forename: Anamika
authors.initials: A
authors.lastname: Dey
authors.affiliation: Centre for Nanotechnology, Indian Institute of Technology Guwahati, Guwahati-781039, India. pki@iitg.ernet.in.
authors.forename: Ashish
authors.initials: A
authors.lastname: Singh
authors.affiliation: Centre for Nanotechnology, Indian Institute of Technology Guwahati, Guwahati-781039, India. pki@iitg.ernet.in.
authors.forename: Dipjyoti
authors.initials: D
authors.lastname: Das
authors.affiliation: Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati-781039, India and Centre for Nanotechnology, Indian Institute of Technology Guwahati, Guwahati-781039, India. pki@iitg.ernet.in.
authors.forename: Parameswar Krishnan
authors.identifier: http://orcid.org/0000-0003-4126-3774
authors.initials: PK
authors.lastname: Iyer