Photo-patternable high-k ZrOx dielectrics prepared using zirconium acrylate for low-voltage-operating organic complementary inverters

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123

Optical memories based on photoresponsive organic field-effect transistors (OFETs) are of great interest due to their unique applications, such as multibit storage memories and flexible imaging circuits. Most studies of OFET-type memories have focused on the photoresponsive active channels, but more useful functions can be additionally given to the devices by using floating gates that can absorb light. In this case, effects of photoirradiation on photoactive floating-gate layers need to be fully understood. Herein, we studied the photoinduced erasing effects of floating-gate interlayers on the electrical responses of OFET-type memories and considered the possible mechanisms. Polymer/C composites were inserted between pentacene and SiO to form photoresponsive floating-gate interlayers in transistor memory. When exposed to light, C generated excitons, and these photoexcited carriers contributed to the elimination of trapped charge carriers, which resulted in the recovery of OFET performance. Such memory devices exhibited bistable current states controlled with voltage-driven programming and light-driven erasure. Furthermore, these devices maintained their charge-storing properties over 10 000 s. This proof-of-concept study is expected to open up new avenues in information technology for the development of organic memories that exhibit photoinduced recovery over a wide range of wavelengths of light when combined with appropriate photoactive floating-gate materials.

Section: Introductionmentioning

confidence: 99%

Photoinduced Recovery of Organic Transistor Memories with Photoactive Floating-Gate Interlayers

Jeong

Yun

Kim

et al. 2017

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123

“…These voltage inversions occur because the p-and n-type OFETs turned on and off, respectively, at small V IN , and vice versa at high V IN . 66 As one of the important figure-of-merit of inverters, the inverter voltage gains, which are defined using dV OUT /dV IN , were calculated from Figure 8c and plotted, as shown in Figure 8d. The maximum gain value reached 43.2 with a V DD of 60 V, which is, to the best of our knowledge, the first demonstration of organic complementary inverters with EHD-printed electrodes that show meaningful inverter performances.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…The inverters operated with a sharp voltage inversion over various ranges of input voltages ( V IN ) with almost negligible hysteresis. These voltage inversions occur because the p- and n-type OFETs turned on and off, respectively, at small V IN , and vice versa at high V IN . As one of the important figure-of-merit of inverters, the inverter voltage gains, which are defined using d V OUT /d V IN , were calculated from Figure c and plotted, as shown in Figure d.…”

Section: Resultsmentioning

confidence: 99%

Direct Printing of Asymmetric Electrodes for Improving Charge Injection/Extraction in Organic Electronics

Tang

Kwon

Hong

et al. 2020

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Engineering the energy levels of organic conducting materials can be useful for developing high-performance organic field-effect transistors (OFETs), whose electrodes must be well controlled to facilitate easy charge carrier transport from the source to drain through an active channel. However, symmetric source and drain electrodes that have the same energy levels are inevitably unfavorable for either charge injection or charge extraction. In this study, asymmetric source and drain electrodes are simply prepared using the electrohydrodynamic (EHD)-jet printing technique after the careful work function engineering of organic conducting material composites. Two types of additives effectively tune the energy levels of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate-based composites. These solutions are alternately patterned using the EHD-jet printing process, where the use of an electric field makes fine jet control that enables to directly print asymmetric electrodes. The asymmetric combination of EHD-printed electrodes helps in obtaining advanced charge transport properties in p-type and n-type OFETs, as well as their organic complementary inverters. This strategy is believed to provide useful guidelines for the facile patterning of asymmetric electrodes, enabling the desirable properties of charge injection and extraction to be achieved in organic electronic devices.

“…The past decade has witnessed major advances in large-area, low-power, mechanically flexible, and wearable electronic devices enabled using thin-film transistors (TFTs) of diverse types. − In this regard, high-dielectric constant (κ) metal oxide dielectric materials such as aluminum oxide (AlO x ) − and zirconium oxide (ZrO x ) − and other unconventional dielectrics such as self-assembled nanodielectrics and composites , hold the key to TFT operation at low driving voltages. , Compared to conventional low-κ silicon dioxide (SiO 2 , κ ∼ 3.9), high-κ oxide materials (κ ∼ 8.8–30) yield significantly higher specific capacitance values for equivalent SiO 2 film thickness and thereby can allow comparable source–drain currents at far lower operating voltages, essential for low-power electronics. , Furthermore, high-κ dielectrics can circumvent the high leakage current of ultrathin SiO 2 (<2 nm) dielectrics, thereby extending Moore’s Law …”

Section: Introductionmentioning

confidence: 99%

Role of Fluoride Doping in Low-Temperature Combustion-Synthesized ZrO_x Dielectric Films

Sil

Goldfine

Huang

et al. 2022

Zirconium oxide (ZrO x ) is an attractive metal oxide dielectric material for low-voltage, optically transparent, and mechanically flexible electronic applications due to the high dielectric constant (κ ∼ 14−30), negligible visible light absorption, and, as a thin film, good mechanical flexibility. In this contribution, we explore the effect of fluoride doping on structure−property−function relationships in low-temperature solutionprocessed amorphous ZrO x . Fluoride-doped zirconium oxide (F:ZrO x ) films with a fluoride content between 1.7 and 3.2 in atomic (at) % were synthesized by a combustion synthesis procedure. Irrespective of the fluoride content, grazing incidence X-ray diffraction, atomic-force microscopy, and UV−vis spectroscopy data indicate that all F:ZrO x films are amorphous, atomically smooth, and transparent in visible light. Impedance spectroscopy measurements reveal that unlike solution-processed fluoride-doped aluminum oxide (F:AlO x ), fluoride doping minimally affects the frequency-dependent capacitance instability of solution-processed F:ZrO x films. This result can be rationalized by the relatively weak Zr−F versus Zr−O bonds and the large ionic radius of Zr +4 , as corroborated by EXAFS analysis and MD simulations. Nevertheless, the performance of pentacene thin-film transistors (TFTs) with F:ZrO x gate dielectrics indicates that fluoride incorporation reduces I−V hysteresis in the transfer curves and enhances bias stress stability versus TFTs fabricated with analogous, but undoped ZrO x films as gate dielectrics, due to reduced trap density.