Schottky barrier and contact resistance of InSb nanowire field-effect transistors

• Published in: Nanotechnology Vol. 27; no. 27; p. 275204
• Main Authors: Fan, Dingxun, Kang, N, Ghalamestani, Sepideh Gorji, Dick, Kimberly A, Xu, H Q
• Format: Journal Article
• Language: English
• Published: England IOP Publishing 08.07.2016
• Subjects: Condensed Matter Physics; contact resistance; Den kondenserade materiens fysik; Engineering and Technology; field-effect transistor; Fysik; InSb; magnetotransport; Nano Technology; Nanoteknik; Nanowire; Natural Sciences; Naturvetenskap; Physical Sciences; Schottky barrier; Teknik
• ISSN: 0957-4484; 1361-6528
• DOI: 10.1088/0957-4484/27/27/275204

Understanding of the electrical contact properties of semiconductor nanowire (NW) field-effect transistors (FETs) plays a crucial role in the use of semiconducting NWs as building blocks for future nanoelectronic devices and in the study of fundamental physics problems. Here, we report on a study of the contact properties of Ti/Au, a widely used contact metal combination, when contacting individual InSb NWs via both two-probe and four-probe transport measurements. We show that a Schottky barrier of height Φ SB ∼ 20 meV is present at the metal-InSb NW interfaces and its effective height is gate-tunable. The contact resistance ( R c ) in the InSb NWFETs is also analyzed by magnetotransport measurements at low temperatures. It is found that R c in the on-state exhibits a pronounced magnetic field-dependent feature, namely it is increased strongly with increasing magnetic field after an onset field B c . A qualitative picture that takes into account magnetic depopulation of subbands in the NWs is provided to explain the observation. Our results provide solid experimental evidence for the presence of a Schottky barrier at Ti/Au-InSb NW interfaces and can be used as a basis for design and fabrication of novel InSb NW-based nanoelectronic devices and quantum devices.