A Low‐Voltage Organic Complementary Inverter with High Operation Stability and Flexibility Using an Ultrathin iCVD Polymer Dielectric and a Hybrid Encapsulation Layer

Abstract

which results in the rapid degradation of organic devices with n-type semiconductors. Several methods have been investigated, such as introducing top-gated device structures [ 12 ] or applying an encapsulation layer on the devices, [ 13,14 ] to prevent the diffusion of water or oxygen into the semiconductors. However, most of the additional layers directly integrated onto the semiconductor usually damage the semiconductor, often causing device failure. [ 15 ] Here, we fabricated a low-voltage organic complementary inverter with a high environmental stability by adopting an ultrathin (typically having a thickness of less than 30 nm) polymer dielectric layer named poly(1,3,5-trivinyl-1,3,5-trimethyl cyclotrisiloxane) (pV3D3) via initiated chemical vapor deposition (iCVD). [ 16 ] The pV3D3 exhibited a high fl exibility and a low leakage current ( J i ) less than 10 −9 A cm −2 up to 5 MV cm −1 with an ultralow thickness down to 10 nm. [ 17,18 ] As well as the dielectric layer for electronic devices, a hybrid encapsulation layer via sequential deposition of iCVD and atomic layer deposition (ALD) was applied directly onto the organic complementary inverter to improve the environmental stability of organic electronic devices. [ 19 ] By adopting these dielectric layers and encapsulation layers together, the newly developed organic complementary inverter in this study exhibited a high gain of 130 V/V at a switching threshold voltage ( V M ) of 1.52 V at a supply voltage of 3 V. It also retained high air stability for more than 3 weeks. Also, devices on fl exible substrates were intact up to 2% of tensile strain, demonstrating its excellent mechanical fl exibility.As p-and n-type semiconductors, dinaphtho[2;3-b:2′,3′-f ]-thieno [3,2-b]thiophene (DNTT) and N , N ′-ditridecylperylene-3,4,9,10-tetracarboxylic diimide (PTCDI-C13) were selected to fabricate the organic complementary inverters. Prior to the examining the electrical characteristics of the complementary inverters, the electrical characteristics of OTFT with each semiconductor were analyzed ( Figure 1 ). The sub-30 nm-thick iCVD pV3D3 layer was mainly used as a gate dielectric layer in both OTFTs. The use of such an ultrathin polymeric dielectric layer enables the operation of both n-and p-type OTFTs below ±5 V, which is critically important to reduce the power consumption. Furthermore, both p-and n-type OTFTs exhibited hysteresisfree operation with a low gate leakage current ( I G ) in the range of 10 −10 A, demonstrating the excellent performance of the OTFTs with the iCVD dielectric layer. The average µ obtained from ten devices was 0.87 ± 0.19 cm 2 V −1 s −1 for DNTT TFT and 0.71 ± 0.02 cm 2 V −1 s −1 for PTCDI-C13 TFT, respectively. The | V T | of each device was also similar to each other (−1.29 V for

Organic Field‐Effect Transistor for Energy‐Related Applications: Low‐Power‐Consumption Devices, Near‐Infrared Phototransistors, and Organic Thermoelectric Devices

“…Apart from high‐ k metal oxide dielectrics, applying solution‐processed or initiated chemical vapor deposition (iCVD) polymer dielectrics with k value comparable or lower than SiO 2 can also reduce the operating voltage of OFETs . The lack of dipoles and hydrophobic nature of most polymer dielectrics may be beneficial for organic semiconductor deposition as well as the electrical performance and stability of OFETs .…”

Negative Transconductance Heterojunction Organic Transistors and their Application to Full‐Swing Ternary Circuits

“…Here, we propose a new heterojunction transistor structure that has a p‐type dinaphtho[2,3‐b:2′,3′‐f]thieno[3,2‐b]thiophene (DNTT) layer on an n‐type N,N ′‐ditridecylperylenediimide (PTCDI‐C13) layer . In contrast to previous conventional H‐TRs in which an electrode makes contact with only a p‐ or n‐type semiconductor ( Figure b), the proposed H‐TR has a p‐type DNTT layer that makes contact with both electrodes (i.e., source and drain).…”

Initiated Chemical Vapor Deposition: A Versatile Tool for Various Device Applications

“…Seong et al presented a uniform, low‐voltage operation of 30 complementary inverters among 37 devices in an area of 75 × 75 mm 2 that consisted of n‐type N,N'‐ditridecylperylene‐3,4,9,10‐tetracarboxylic diimide (PTCDI) and p‐type DNTT semiconductors with a ca . 30 nm‐thick pV3D3 gate dielectric . An iCVD gate dielectric is also compatible with carbon nanotube (CNT)‐based TFT logic circuits .…”