Performance Enhancement of Solution Processable Organic Thin Film Transistors by Newly Approached Solution Process
- 주제(키워드) Organic Thin Film Transistor , Solution Process
- 발행기관 고려대학교 대학원
- 지도교수 홍문표
- 발행년도 2012
- 학위수여년월 2012. 2
- 학위구분 박사
- 학과 일반대학원 응용물리학과
- 세부전공 디스플레이·반도체소자전공
- 원문페이지 139 p
- 실제URI http://www.dcollection.net/handler/korea/000000033229
- 본문언어 영어
- 제출원본 000045700459
초록/요약
While fabrication of organic thin film transistor (OTFT) with all solution procession, interface reactions between organic functional layers including polymeric organic gate insulator (OGI), soluble organic semiconductor (OSC) and organic passivation (OP) were analyzed. Firstly, we developed that the ameliorated poly (4-vinyl phenol) (PVP) OGIs were synthesized by inducing a ring shape phenol backbone structure, which led to the localization of the hydroxyl group. The hysteresis behaviors from the operation of ameliorated resin based solution processable OTFTs in humidified air can verify that the new PVP resin drives nearly hysteresis free, and excellent air stability with ultra low slow polarization. When the new PVP dipped in polar solvent (tetralin), the new PVP-OTFT was confirmed their good chemical resistance and derived higher & stable TFT performance. Secondly, a threshold voltage (Vth) shift is usually exhibited when GIs are exposed in an ambient air condition. This phenomenon was caused by the absorbed polar components (i.e. oxygen and moisture) on the interface between GIs and soluble OSCs during the jetting process. In our research, interface treatments on the various dielectric surfaces (including inorganic and organic dielectric materials such as silicon nitride (SiNx) and PVP were examined with ammonia (NH3) plasma treatment for SiNx insulator and high vacuum seasoning for PVP insulator. These results of each OTFT devices show that polar components were well eliminated by the surface treatment processes. Also, the optimization of solution processable OTFT made of soluble OSC with drying conditions, a substrate temperature, a solvent annealing, and an impermanent surface treatment significantly. Finally, to reduce the chemical damage by the soluble passivation material on the OSC, we developed a new passivation material (ANBm) based on designed monomers without using a solvent. However, we also found that the degradation of OTFTs performance is mainly caused by physical damage by soluble materials that penetrate into the interface. The highly stable “Single Layer Passivated OTFTs” was successfully fabricated by the soluble passivation process without a pin hole in active area using an attack-free material. As a result, we studied the interface of organic layer in solution processable OTFT. Especially, we found that the significantly value of interface chare trap densities with solution processable OTFT samples. We calculated to average mean about 5.0*10^11 (cm2eV)^(-1). We considered that it is important value in solution processable OTFT region.
more목차
CHAPTER 1. Introduction 1
1. Flexible Display and Solution Prcossable Technique 1
2. Organic Thin Film Transistor 8
2.1. Introduction 8
2.2. Principle of Operation 11
3. Thesis Statement 17
CHAPTER 2. Study of Interface between Organic Gate Insulator and Organic Semiconductor with Solution Processable OTFT 23
1. Organic Dielectric for Soluble OTFT 23
1.1. New poly (4-vinyl phenol) (PVP) 23
1.1.1 Experimental & Discussion 24
1.1.2 Summary 34
1.2. Interface of Polymer-Polymer Layer with Solution Processable OTFT 36
1.2.1 Experimental & Discussion 36
1.2.2 Summary 45
CHAPTER 3. Surface Treatment of Gate Insulators for Solution Processable OTFT 47
1. Plasma Treatment on Inorganic Gate Dielectric for Solution Processable OTFT 47
1.1. Introduction 47
1.2. Experimental 49
1.3. Results and Discussion 50
1.3.1 Improvement of the channel interface of SiNx 50
1.3.2 The improvement of Contact Resistance 56
1.4. Summary 62
2. High Vacuum Seasoning for Solution Processable OTFT 65
2.1. High Vacuum Seasoning 65
2.2. Experimental & Discussion 66
2.3. Summary 74
CHAPTER 4. Improvement of Performance with Process Parameter of Solution Processable OTFT 77
1. Large Grain of Soluble OSC with Drying Process 77
1.1. Experimental & Discussion 78
1.2. Summary 85
2. Solvent Annealing 86
2.1. Experimental & Discussion 86
2.2. Summary 91
CHAPTER 5. Passivation for All Solution Processable OTFT 92
1. Introduction 92
2. Experimental 93
3. Results and Discussion 97
3.1. Solvent Attack-Free Passivation 97
3.2. Simulation of the Degradation Mechanism 99
3.3. Long Term Stability for OTFTs 102
4. Summary 107
CHAPTER 6. Incompleted Work for Solution Processable OTFT 110
1. Development of Selective Self Assembled Treatment 110
1.1. Selective Assembled Treatment (SST) 110
2. Development of Impermanent Surface Treatment 113
2.1. Impermanent Surface Treatment (IST) 113
PUBLICATIONS (Only SCI journal) 116
