Pulkit Saxena

Bio: Pulkit Saxena is an academic researcher from Indian Institute of Technology, Jodhpur. The author has contributed to research in topics: Field-effect transistor & Low voltage. The author has an hindex of 1, co-authored 5 publications receiving 9 citations.

Solution-Processed Flexible Organic Field-Effect Transistors with Biodegradable Gelatin as the Dielectric Layer: An Approach Toward Biodegradable Systems

Abstract: High-performance flexible organic field-effect transistors with natural protein gelatin as a dielectric layer and solution-processed TIPS-pentacene as an active layer were fabricated on a flexible ...

Low Voltage Organic Field-Effect Transistors with Room Temperature Deposited Dielectric Layer

Abstract: Lowering the processing temperature is a crucial factor in the development of flexible electronic devices. Here we report the fabrication of high-performance OFETs based on room temperature deposited Ba0.5Sr0.5TiO3 (BST) as a high-k dielectric layer. The fabricated devices exhibited excellent performance while operating at a low voltage of -3 V along with demonstrating high operational stability when tested for 1 h bias stress and continuous transfer measurement cycles. In addition, inverter circuit performance is also investigated with these devices by connecting them to external loads.

Effect of Annealing on Low-Voltage Organic Field-Effect Transistors with P(VDF-TrFE) Gate Dielectric

Abstract: In this work, solution-processed low voltage organic field-effect transistors (OFETs) are demonstrated using P(VDF-TrFE) as the primary gate dielectric with TIPS-Pentacene: Polystyrene (PS) blend on top, providing an active layer. Maximum field-effect mobility of ~0.6 cm2 V−1s−1 with an average of ~ 0.4 (±0.1) cm2 V−1s−1 in saturation region and high Ion/Ioff value of ~104 were achieved from these devices at an operating voltage of -5V. Moreover, these devices exhibited excellent electrical stability upon multiple scans of transfer characteristics and under bias-stress. A deterioration in the performance of OFETs was observed upon annealing at temperatures over 50 °C.

High Performance Flexible Transistors With Polyelectrolyte/Polymer Bilayer Dielectric

Abstract: Flexible organic field-effect transistors (OFETs) consisting of polyvinyl alcohol (PVA)/ polyelectrolyte polyacrylic acid (PAA) bilayer gate dielectric are demonstrated. These devices exhibited maximum field-effect mobility of $\mu _{\text {max}} ~\sim {0.94}$ cm $^{{2}}\cdot \text{V}^{-{1}}\cdot \text{s}^{-{1}}$ with an average of $\mu _{\text {avg}} ~\sim {0.7}$ (±0.1) cm $^{{2}}\cdot \text{V}^{-{1}}\cdot \text{s}^{-{1}}$ in the saturation regime and ${I}_{ \mathrm{\scriptscriptstyle ON}}/{I}_{ \mathrm{\scriptscriptstyle OFF}}$ of $\sim 10^{{4}}$ with an operating voltage of −5 V. Apart from high electrical stability upon bias stress and repeated measurement of transfer curves, these devices showed excellent stability in electrical performance upon being subjected to sequential bending in various directions, i.e., vertical, horizontal, and diagonal to the channel length. Even after the application of 500 cycles of bending, no significant degradation in ${I}_{ \mathrm{\scriptscriptstyle ON}}$ was observed. This very high electromechanical stability in devices was achieved due to a super strong and highly tough hydrogen-bonded polyelectrolyte/polymer bilayer dielectric. In addition, external resistor-loaded inverters were also demonstrated with these devices to evaluate the circuit performance.

Tailoring Molecular Weight of Polymer Additives for Organic Semiconductors

Abstract: A binary system comprising both an organic semiconductor and a polymer additive has attracted extensive research interests due to great potential for high-performance, solution-proccessable electronic devices on flexible substrates. The...

Multifunctional Flexible Organic Transistors with a High-k/Natural Protein Bilayer Gate Dielectric for Circuit and Sensing Applications

Abstract: Organic field-effect transistors (OFETs) have opened up new possibilities as key elements for skinlike intelligent systems, due to the capability of possessing multiple functionalities. Here, multifunctional OFET devices based on gelatin, a natural biopolymer gate dielectric, and TIPS-pentacene as an organic semiconductor are extensively explored. Gelatin is combined with a thin high-k HfO2 dielectric layer deposited by atomic layer deposition (ALD) to achieve a low leakage current and low-voltage operation. The natural biopolymer offers a better semiconductor:dielectric interface, leading to better charge conduction in the devices, along with an enhancement of sensing capabilities giving additional functionality. These fabricated flexible OFET devices exhibit excellent electrical characteristics with a high field-effect mobility reaching over 2 cm2/(V s) (extracted with Ci at 1 kHz), a low subthreshold swing (SS) of ∼200 mV/dec, and a high current on–off (Ion/Ioff) ratio at a low operating voltage of −5 V with excellent electrical and mechanical stability. Moreover, circuit and multiparameter sensing capabilities for visible and UV light, as well as for humidity and breath rate, have been successfully demonstrated for these devices. Our results indicate that these multifunctional OFET devices can open up a plethora of opportunities for practical applications such as real-time health and environmental monitoring.

Impact of Planar and Vertical Organic Field‐Effect Transistors on Flexible Electronics

Abstract: The development of flexible and conformable devices, whose performance can be maintained while being continuously deformed, provides a significant step toward the realization of next‐generation wearable and e‐textile applications. Organic field‐effect transistors (OFETs) are particularly interesting for flexible and lightweight products, because of their low‐temperature solution processability, and the mechanical flexibility of organic materials that endows OFETs the natural compatibility with plastic and biodegradable substrates. Here, an in‐depth review of two competing flexible OFET technologies, planar and vertical OFETs (POFETs and VOFETs, respectively) is provided. The electrical, mechanical, and physical properties of POFETs and VOFETs are critically discussed, with a focus on four pivotal applications (integrated logic circuits, light‐emitting devices, memories, and sensors). It is pointed out that the flexible function of the relatively newer VOFET technology, along with its perspective on advancing the applicability of flexible POFETs, has not been reviewed so far, and the direct comparison regarding the performance of POFET‐ and VOFET‐based flexible applications is most likely absent. With discussions spanning printed and wearable electronics, materials science, biotechnology, and environmental monitoring, this contribution is a clear stimulus to researchers working in these fields to engage toward the plentiful possibilities that POFETs and VOFETs offer to flexible electronics.