Sains Malaysiana 39(4)(2010): 615–620

Dependence of Band Structure and Carrier Concentration of Metallic (13,13) and Semiconducting (13,0) Single Wall Carbon Nanotube on Temperature

(Kebergantungan Struktur Jalur dan Kepekatan Pembawa untuk Nanotiub Karbon Berdinding Tunggal yang Bersifat Logam (13,13) dan Semikonduktor (13,0) Terhadap Suhu)

J. Karamdel^1,2,*, M. Damghanian¹, F. Razaghian², C.F. Dee¹ & B. Yeop Majlis¹

¹Institute of Microengineering and Nanoelectronics (IMEN)

University Kebangsaan Malaysia, 43600, Bangi, Selangor, D.E., Malaysia

²Electrical Department, Faculty of Engineering

Islam Azad University-South Tehran Branch, No. 209 North Iranshahr Ave Tehran, Iran

Diserahkan: 28 Ogos 2009 / Diterima: 17 November 2009

ABSTRACT

The electronic band structure, density of states (DOS) and carrier concentration of a (13,13) metallic and a (13,0) semiconducting Single Wall Carbon Nanotube (SWCNT) have been estimated and simulated by using the Fermi-Dirac distribution function. The energy dispersion E(k) relation for metallic SWCNT near the minimum energy is linear and the Fermi level was independent of temperature (T). On the other hand for semiconducting SWCNT the E(k) relation is parabolic. The normalized Fermi-Energy (E_F – E_C) in the nondegenerate regime is a weak (logarithmic) function of carrier concentration and varies linearly with T. In the degenerate condition, the Fermi level was independent of T and was a strong function of carrier concentration.

Keywords: Band structure; carbon nano-tube; carrier statistic; Fermi level

ABSTRAK

Struktur jalur elektronik,  ketumpatan keadaan dan kepekatan pembawa bagi nanotiub karbon berdinding tunggal (SWCNT) yang bersifat logam dan semikonduktor telah dianggarkan dengan menggunakan fungsi taburan Fermi-Dirac. Hubungan E(k) berdekatan dengan tenaga minimum adalah mendatar dan aras Fermi adalah bebas daripada pengaruh suhu (T) untuk SWCNTs yang bersifat logam. Manakala, untuk SWCNTs yang bersifat semikonduktor, hubungan E(k) adalah parabolik. Tenaga Fermi-ternormal (E_F – E_C) dalam regim tak-degenerat mempunyai fungsi ketumpatan pembawa (logaritma) yang lemah dan berubah secara linear dengan T. Dalam keadaan degenerat, aras Fermi tidak bergantung dengan T dan adalah satu fungsi yang bergantung kuat dengan kepekatan pembawa.

Kata kunci: Aras Fermi; nanotiub karbon; statistik pembawa; struktur jalur

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*Pengarang untuk surat-menyurat; email: jkaramdel@yahoo.com