{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Molecular dynamics simulations of carbon nanotube-silicon interfacial

Molecular dynamics simulations of carbon nanotube-silicon interfacial

Info icon This preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Molecular dynamics simulations of carbon nanotube/silicon interfacial thermal conductance Jiankuai Diao, 1, a Deepak Srivastava, 1, b and Madhu Menon 2, c 1 University Affiliated Research Center, University of California, Santa Cruz and NASA Ames Center for Nanotechnology, Moffett Field, California 94035, USA 2 Department of Physics and Astronomy, and Center for Computational Sciences, University of Kentucky, Lexington, Kentucky 40506, USA Received 25 January 2008; accepted 8 March 2008; published online 22 April 2008 Using molecular dynamics simulations with Tersoff reactive many-body potential for Si–Si, Si–C, and C–C interactions, we have calculated the thermal conductance at the interfaces between carbon nanotube CNT and silicon at different applied pressures. The interfaces are formed by axially compressing and indenting capped or uncapped CNTs against 2 1 reconstructed Si surfaces. The results show an increase in the interfacial thermal conductance with applied pressure for interfaces with both capped and uncapped CNTs. At low applied pressure, the thermal conductance at interface with uncapped CNTs is found to be much higher than that at interface with capped CNTs. Our results demonstrate that the contact area or the number of bonds formed between the CNT and Si substrate is key to the interfacial thermal conductance, which can be increased by either applying pressure or by opening the CNT caps that usually form in the synthesis process. The temperature and size dependences of interfacial thermal conductance are also simulated. These findings have important technological implications for the application of vertically aligned CNTs as thermal interface materials. © 2008 American Institute of Physics . DOI: 10.1063/1.2905211 I. INTRODUCTION As the size of the electronic circuits in microprocessors decreases and their density increases, there is a correspond- ing increase in the heat generation. Metallic heat sink mate- rials such as copper are usually attached to electronic devices to help dissipate the heat generated in electronic devices into the environment. The thermal conductance at interfaces formed by bringing two solid surfaces that were originally separated into contact, however, is generally low due to the very low effective contact area less then a few percent at the interface. 1 This low effective contact area stems from the fact that solid surfaces are usually rough at the atomic level. To increase the effective contact area and thereby the inter- facial thermal conductance, thermal interface materials such as a thermal grease are commonly used in the electronic industry, e.g., in between microprocessor chips and heat sink materials. 1 The usefulness of thermal grease derives from the fact that it is an extremely flexible material that can form an efficient contact with both solid surfaces under pressure, ef- fectively increasing the contact area between the original two solid surfaces. The thermal conductivity of the thermal grease itself is, however, low.
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern