Insights into the Interfacial Properties of Low-Voltage CuPc Field-Effect Transistor

详细信息    查看全文

• 作者：Yaorong Su ; Ming Ouyang ; Pengyi Liu ; Zhi Luo ; Weiguang Xie ; Jianbin Xu
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2013
• 出版时间：June 12, 2013
• 年：2013
• 卷：5
• 期：11
• 页码：4960-4965
• 全文大小：422K
• 年卷期：v.5,no.11(June 12, 2013)
• ISSN：1944-8252

文摘

The interfacial transport properties and density of states (DOS) of CuPc near the dielectric surface in an operating organic field-effect transistor (OFET) are investigated using Kelvin probe force microscopy. We find that the carrier mobility of CuPc on high-k Al₂O_y/TiO_x (ATO) dielectrics under a channel electrical field of 4.3 脳 10² V/cm reaches 20 times as large as that of CuPc on SiO₂. The DOS of the highest occupied molecular orbital (HOMO) of CuPc on the ATO substrate has a Gaussian width of 0.33 卤 0.02 eV, and the traps DOS in the gap of CuPc on the ATO substrate is as small as 7 脳 10¹⁷ cm^鈥?. A gap state near the HOMO edge is observed and assigned to the doping level of oxygen. The measured HOMO DOS of CuPc on SiO₂ decreases abruptly near E_VGS聽=聽VT, and the pinning of DOS is observed, suggesting a higher trap DOS of 10¹⁹鈥?0²⁰ cm^鈥? at the interface. The relationships between DOS and the structural, chemical, as well as electrical properties at the interface are discussed. The superior performance of CuPc/ATO OFET is attributed to the low trap DOS and doping effect.

Keywords:

organic field-effect transistor; density of state; Kelvin probe force microscopy; interface; high-k