Floating Back-Gate Field Effect Transistor Fabricated Using a Single Nanowire of Charge Transfer Complex as a Channel

Abstract

Metal−organic charge transfer complex (MOCT) material have good application potentials. We report a high carrier mobility in MOCT material Cu:tetracyanoquinodimethane (Cu:TCNQ) single nanowire (NW). A novel floating backgate field effect transistors is fabricated using Cu:TCNQ single NW of diameter ranging from ∼50 to 100 nm and length ∼1.0− 2.0 μm as channel material. Floating gate is made of conducting Si (c-Si) electrically isolated from the environment by thermally grown SiO 2 (100 nm thickness) all around it, which is an easy and inexpensive approach to reduce leakage current and improve the device performance. The devices can exhibit on/off current ratio of ∼10 2 −10 4 at room temperature. Mobility of the NW channel as measured in different single NW devices is ∼4.3 × 10 2 to 1.2 × 10 4 cm 2 V −1 s −1 which is the best reported mobility in such molecular materials. The observed high mobility has been proposed to arise from π−π stacking of the molecular orbitals of donor−acceptor type CT materials and good crystallinity and also small device size that reduces carrier scattering.

Transistor Characteristics of Charge-Transfer Complexes Observed across a Neutral–Ionic Transition

“…Organic metals have been used in transistors in a very thin form. Field-effect doping to the κ-type Mott insulator leads to field-induced superconducting state. , PEDOT:PSS makes depletion-type transistors (PEDOT:poly­(3,4-ethylenedioxy thiophene) and PSS:poly­(styrene sulfonate)). − These transistors have achieved very high mobility exceeding 100 cm 2 V –2 s –1 . However, there is no systematic study of transistor properties in a wide range of charge-transfer degrees, particularly across a neutral–ionic transition.…”

Self-Powered Photodetector Fabricated from a Single-Charge-Transfer Complex Nanowire Grown In Situ between Prefabricated Electrodes on an Si3N4 Membrane

“…The Cu:TCNQ is a widely explored semiconducting material in the metal-organic charge transfer complex family. − It is mostly known for its electrical resistive state switching and optoelectronic transport properties. The Cu:TCNQ in its NW form has attracted much attention because of its highly anisotropic one-dimensional fascinating structure, unique electronic and optical properties, high mobility, and potential applications in electrical and optical memory devices , like high-mobility field-effect transistors, sensors etc. Although, optical detectors fabricated from a single strand and array of Cu:TCNQ NW, , as well as array of NWs, have been reported, there are no reports on SPOD made from a single NW or arrays of Cu:TCNQ NWs with relatively high responsivity.…”

Silicon Nanowire Arrays with Nitrogen-Doped Graphene Quantum Dots for Photodetectors

“…2,3 Thus, changes in the length, diameter, and spacing of SiNWs developed after the etching process reveal improvement of material properties, such as light absorption and scattering, 4 enhancement of surface built-in-field, 5,6 electron−hole recombination, 4 quantum confinement, 7 and so forth. This leads to the enhanced application in photodetectors, 8−12 photovoltaics 13 high sensitivity sensors, 14,15 field-effect-transistors, 16,17 thermoelectric devices, 18 super capacitors, 19 and so on. Single-crystalline SiNWs can be synthesized via reactive-ion-etching (RIE) 20 or vapor−liquid−solid (VLS) 21 methods in gas phase and metalassisted chemical etching (MACE) in the solution process.…”

“…One dimensional (1-D) SiNWs have enhanced light absorption capability and received increasing research interest because of their higher surface-to-volume ratio, strong light trapping effect, fast charge transport, and high charge collection efficiency by shortening the carrier transport path in comparison to bulk Si. , Thus, changes in the length, diameter, and spacing of SiNWs developed after the etching process reveal improvement of material properties, such as light absorption and scattering, enhancement of surface built-in-field, , electron–hole recombination, quantum confinement, and so forth. This leads to the enhanced application in photodetectors, − photovoltaics high sensitivity sensors, , field-effect-transistors, , thermoelectric devices, super capacitors, and so on. Single-crystalline SiNWs can be synthesized via reactive-ion-etching (RIE) or vapor–liquid–solid (VLS) methods in gas phase and metal-assisted chemical etching (MACE) in the solution process.…”