Sains Malaysiana 42(2)(2013): 187–192

Fabrication and Transport Performance Characterization of

Chemically-doped Three-branch Junction Graphene Device

(Fabrikasi dan Ciri Prestasi Angkutan Peranti Grafin Berstruktur Tiga Cabang yang Didop Secara Kimia)

Shaharin Fadzli Abd Rahman*

Faculty of Electrical Engineering, Universiti Teknologi Malaysia 81310 UTM Skudai, Johor, Malaysia

Seiya Kasai

Graduate School of Information Science and Technology and Research Center for Integrated Quantum Electronics, Hokkaido University N14, W9, Sapporo 060-0814, Japan

Abdul Manaf Hashim

Malaysia-Japan International Institute of Technology (MJIIT), Universiti Teknologi Malaysia International Campus, Jalan Semarak, 54100 Kuala Lumpur, Malaysia

Received: 7 January 2012 / Accepted: 21 May 2012

ABSTRACT

A graphene-based three-branch nanojunction (TBJ) device having nanowire width of 200 nm was successfully fabricated. The layer number of graphene prepared by mechanical exfoliation was determined using a simple optical contrast method which showed good agreement with theoretical value. n-type doping by Polyethylene imines (PEI) was done to control the position of Dirac point. Baking and PEI doping was found to decrease contact resistance and increase the carrier mobility. The chemically-doped TBJ graphene showed carrier mobility of 20000 cm²/Vs, which gave related mean free path of 175 nm.

Keywords: Chemical doping; graphene; three-branch junction device

ABSTRAK

Peranti berstruktur tiga cabang (TBJ) daripada grafin yang mempunyai cabang selebar 200 nm telah berjaya difabrikasi. Bilangan lapisan grafin yang telah disediakan menggunakan kaedah pengelupasan secara mekanikal, telah ditentukan menggunakan kaedah kontras optik yang mudah, dan keputusan uji kaji selari dengan nilai teori. Pendopan kepada jenis-n telah dibuat menggunakan polyethylene imines (PEI) untuk mengawal kedudukan titik Dirac. Pemanasan dan pendopan oleh PEI didapati telah merendahkan rintangan sentuhan logam dan menaikkan mobiliti pembawa. Grafin TBJ yang didop secara kimia telah menunjukkan mobiliti pembawa setinggi 20000 cm²/Vs, menjadikan purata laluan bebas sejauh 175 nm.

Kata kunci: Grafin; pendadahan secara kimia; peranti berstruktur tiga cabang

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*Corresponding author; email: shaharinfadzli@fke.utm.my