Electrical contacts to carbon nanotubes down to 1nm in diameter

Kim, Woong; Javey, Ali; Tu, Ryan; Cao, Jiefeng; Wang, Qian; Dai, Hongjie

doi:10.1063/1.2108127

Cited by 213 publications

(190 citation statements)

References 18 publications

(22 reference statements)

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“…The fact that the devices belong to the same wafer exclude all the other reasons such as different metal material or different fabrication process to explain this different behavior. A non uniformity in annealing, NW doping level [8,9] and high interface traps density (that pins the Fermi level) as well as the high sensitivity of the metal-NW contact to local surface contaminations [10][11][12][13] might explain the different SBs between S and D. In [11][12][13] the researchers noticed a similar behavior with non linear I-Vs of Carbon Nanotube (CNT) FETs. Lu et al [12] used intentionally a chemical in the process of one of the two metal contacts surface of a CNTFET and they noted asymmetric I-Vs due to the different SB of S and D. Moreover, they presented some ab initio calculations and they showed the increased sensitivity of the metal work-function to these chemicals.…”

Section: Discussionsupporting

confidence: 55%

“…Lu et al [12] used intentionally a chemical in the process of one of the two metal contacts surface of a CNTFET and they noted asymmetric I-Vs due to the different SB of S and D. Moreover, they presented some ab initio calculations and they showed the increased sensitivity of the metal work-function to these chemicals. Kim et al [13] showed that remaining from the PMMA (due to imperfect development) during the lift off process step might have an impact to the SB of the contacts. More specialized experiments should be performed in order to identify the origin of Materials Science Forum Vols.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Effect of Source and Drain Contacts Schottky Barrier on 3C-SiC Nanowire FETs I-V Characteristics

Rogdakis¹,

Lee

Kim

et al. 2009

MSF

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Abstract. In this work, SiC nanowire (NW) FETs are prepared and their electrical measurements are presented. From the samples fabricated on the same substrate, various I-Vs shapes are obtained (linear, non linear symmetric, and asymmetric). With the assistance of simulation, we show that this is a result of different values of Schottky Barrier Heights (SBH) at Source (S) / Drain (D) contacts of FETs. An origin for this might be a non uniformity in annealing, NW doping level and high interface traps density (that pins the Fermi level) as well as the high sensitivity of the metal-NW contacts to local surface contaminations.

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Section: Discussionsupporting

confidence: 55%

Section: Discussionmentioning

confidence: 99%

Effect of Source and Drain Contacts Schottky Barrier on 3C-SiC Nanowire FETs I-V Characteristics

Rogdakis¹,

Lee

Kim

et al. 2009

MSF

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“…Kim et al have demonstrated that the on-state current depends on the diameter of the CNT also for metallic CNTs, a somewhat surprising result considering that there should be no Schottky barrier present between metal contacts and metallic CNTs. 90 The authors attribute the diameter dependence of metallic CNTs to the increase of the chemical reactivity of CNTs with decreasing diameter which may lead to a large perturbation of the electronic structure of the CNTs underneath the contacts. Au and Pt have work functions similar to Pd but CNTFETs using these metals as contacts still exhibit low on-currents which have been attributed to the weaker adhesion of these metals to CNTs.…”

Section: A Measurements Of Schottky Barrier Heightsmentioning

confidence: 99%

Schottky barriers in carbon nanotube-metal contacts

Svensson

Campbell

2011

Journal of Applied Physics

175

132

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Contact resistance between metal and carbon nanotube interconnects: Effect of work function and wettability Applied Physics Letters 95, 264103 (2009) Semiconducting carbon nanotubes (CNTs) have several properties that are advantageous for field effect transistors such as high mobility, good electrostatics due to their small diameter allowing for aggressive gate length scaling and capability to withstand high current densities. However, in spite of the exceptional performance of single transistors only a few simple circuits and logic gates using CNTs have been demonstrated so far. One of the major obstacles for large scale integration of CNTs is to reliably fabricate p-type and n-type ohmic contacts. To achieve this, the nature of Schottky barriers that often form between metals and small diameter CNTs has to be fully understood. However, since experimental techniques commonly used to study contacts to bulk materials cannot be exploited and studies often have been performed on only single or a few devices there is a large discrepancy in the Schottky barrier heights reported and also several contradicting conclusions. This paper presents a comprehensive review of both theoretical and experimental results on CNT-metal contacts. The main focus is on comparisons between theoretical predictions and experimental results and identifying what needs to be done to gain further understanding of Schottky barriers in CNT-metal contacts.

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“…The resistance of pristine mSWNTs yielded (479 6 193) kX and is comparable to 1.2 nm diameter mSWNTs on Pd electrodes. 16 mSWNTs with nanogaps had a resistance of (643 6 311) TX, which is nine orders of magnitude higher than in pristine devices. We attempted to measure tunneling or field-emission currents through the air gap and to correlate the current with the HIM derived gap size.…”

mentioning

confidence: 99%