Thermionic Field Emission Transport in Carbon Nanotube Transistors

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• 作者：David J. Perello ; Seong Chu Lim ; Seung Jin Chae ; Innam Lee ; Moon. J. Kim ; Young Hee Lee ; Minhee Yun
• 刊名：ACS Nano
• 出版年：2011
• 出版时间：March 22, 2011
• 年：2011
• 卷：5
• 期：3
• 页码：1756-1760
• 全文大小：834K
• 年卷期：0
• ISSN：1936-086X

文摘

With experimental and analytical analysis, we demonstrate a relationship between the metal contact work function and the electrical transport properties saturation current (I_sat) and differential conductance (σ_sd = ∂I_sd/∂V_sd) in ambient exposed carbon nanotubes (CNT). A single chemical vapor deposition (CVD) grown 6 mm long semiconducting single-walled CNT is electrically contacted with a statistically significant number of Hf, Cr, Ti, Pd, and Au electrodes, respectively. The observed exponentially increasing relationship of I_sat and σ_sd with metal contact work function is explained by a theoretical model derived from thermionic field emission. Statistical analysis and spread of the data suggest that the conduction variability in same CNT devices results from differences in local surface potential of the metal contact. Based on the theoretical model and methodology, an improved CNT-based gas sensing device layout is suggested. A method to experimentally determine gas-induced work function changes in metals is also examined.