Complementary-Like Inverter Based on Organic-Inorganic Heterojunction Ambipolar Transistors on Flexible Substrate

Zhaohan Peng,Huijuan Sun,Chao Jiang,Yanjie Wang,Jiawei Wang,Fengjing Liu

doi:10.1109/jeds.2021.3113557

Abstract

Flexible electronic devices featured with miniaturization, light weight and integration, can meet the needs of new generation mobile electronics, and thus have received extensive attention. Obtaining the stable logic devices on flexible substrates is a prerequisite for the application of flexible electronic devices. In this paper, we report the fabrication of organic-inorganic heterojunction ambipolar transistors on flexible Polyimide (PI) substrate and the application of ambipolar transistors in logic circuits. The ambipolar transistors are fabricated by directly depositing p-type organic material dioctylbenzothieno[2,3-b]benzothiophene (C8-BTBT) on amorphous indium-gallium-zinc oxide (a-IGZO) TFT. The fabricated ambipolar transistors with vertically stacked structure show obviously V shape transfer characteristic curves. In addition, the complementary-like inverter is realized with two identical heterojunction ambipolar transistors, which can work in both first and third quadrants. This work provides a method of processing heterojunction ambipolar transistors on flexible substrate by almost fully photolithographic steps, which shows possible potential in the field of flexible electronics devices.

Highlights

Flexible electronic devices featured with miniaturization, light weight and integration, have broad application prospects in various fields such as flexible integrated circuits (IC) [1]–[3]
Organic-inorganic heterojunction ambipolar transistors and inverters preparation: After the fabrication of amorphous indium-gallium-zinc oxide (a-IGZO) TFT arrays on PI flexible substrate, 100 nm organic molecule C8-BTBT was thermally evaporated on a-IGZO surface by vacuum thermal deposition system
After depositing Al2O3, the surface flatness has been significantly improved in which the roughness of flexible substrate decreases from 0.92 nm to 0.21 nm, which guarantees the performance of subsequent devices

Summary

INTRODUCTION

Flexible electronic devices featured with miniaturization, light weight and integration, have broad application prospects in various fields such as flexible integrated circuits (IC) [1]–[3]. Compared with complementary metal oxide semiconductor (CMOS) inverter, complementary-like inverter doesn’t need separated n channel and P channel, can be fabricated by two identical ambipolar transistors. This makes it has the advantages of reduced preparation processes and low cost, attracting a lot of attention [4]. The flexible substrate material must have good mechanical properties to withstand repeated stretching, curling and folding, and has higher requirements for its thermal stability, solvent resistance, and surface smoothness. Our work provides a method of processing ambipolar transistors on flexible substrate, which may show potential in flexible logic circuits

EXPERIMENT SECTION

RESULTS AND DISCUSSION

CONCLUSION