Functional Field-effect Transistors Research Articles

Signatures of Mesoscopic Transport in Single Non‐Intentionally Doped GaN‐Nanowire Field‐Effect Transistors

In this work, the fabrication and characterization of a fully functional field‐effect transistor (FET) are addressed based on a non‐intentionally doped GaN‐nanowire FET (NW–FET). Universal conductance fluctuations (UCFs) are observed at temperatures below 140 K. In contrast to other reports in literature, UCFs appear in the analyzed NW–FET only under the influence of an electrical field when applying a gate voltage, while no UCF signatures are observed when performing magnetic‐field‐dependent measurements. The reason is the considerable impact of the applied voltage on the narrow conductive channel of the non‐intentionally doped NW. The electrical field influences the Fermi level as well as the width of the depletion region, both changing the effective impurity distribution which determines the set of possible electron paths. The electric‐field‐induced variation of the set of electron paths correlates with a conductance variation, which leads to the occurrence of UCFs. Furthermore, the reliability of determining the phase coherence length from the NW–FET transfer characteristics is analyzed. It is shown that the value of is significantly affected by the choice of the gate voltage range due to the current dependence of the magnitude of the UCFs.

Organic–inorganic hybrid perovskite materials and their application in transistors

Hybrid organic–inorganic perovskites (HOIPs) are emerging materials for versatile electronics. This review focuses on the HOIP-based field-effect transistor (FET) and the potential applications of HOIPs in functional FETs.

Transistor-based immunosensing in human serum samples without on-site calibration

Health monitoring and disease diagnostics are increasingly moving away from central laboratories towards the point of need. Despite tremendous progress in transducer research, the general need for sample preparation and calibration has impeded wide-spread adoption of new biosensor technologies. In this work, we realize an on-site calibration-free biosensor by using “differential” readout of pairs of differently functionalized field-effect transistors (FET). Specifically, biosensor 1 carries capture antibodies for the target of interest while biosensor 2 is passivated with a blocking agent. We found that their real-time signal difference is largely unaffected by non-specific binding, drift or device-to-device variations. Using this system, highly sensitive detection of a clinically relevant model antigen, thyroid-stimulating hormone, is demonstrated. The sensors are validated in human serum samples vs. a state-of-the-art central laboratory analyzer. The FET-based platform reaches over 4 orders of magnitude dynamic range with a sub-picomolar lower detection limit and an upper detection limit superior to the state-of-the-art system (>10 nM vs. ˜0.1 nM). In contrast to existing technology, the FET sensors do not require any expensive optical components, labelled detection antibodies, sample pre-treatment or washing steps, and remove the need for sensor calibration. These results represent a critical step towards clinical testing outside the centralized lab.

Memory window in ferroelectric PVDF copolymer gate integrated MOSFET devices for nondestructive readout memory application

AbstractMetal-Ferroelectric-Oxide-Si (MFEOS) field effect transistor (FET) with ferroelectric polyvinylidene fluoride trifluoroethylene copolymer (PVDF-TrFE) gate for nonvolatile memory application is demonstrated. Memory window ascribed to ferroelectric polarization switching has been quantified by shift of threshold voltage are ~ 4-5V. Non saturating IDS is due to free ionic polarization field. IDS-VDS characteristics of functional FET are realized after AC poling.