Work

Contacting Mechanically Exfoliated β-Ga2O3Nanobelts for (Opto)electronic Device Applications

Year: 2016

Type: article

Abstract: We systematically investigated the properties of metal contacts deposited on exfoliated β-Ga 2 O 3 nanobelts. Unintentionally doped β-Ga 2 O 3 was mechanically exfoliated from bulk β-Ga 2 O 3 crystal and transferred onto SiO 2 /Si substrate having a back gate configuration. Electrodes were formed by depositing Ti/Au or Ni/Au onto the transferred β-Ga 2 O 3 nanobelts, followed by rapid thermal annealing (RTA) with different ambient gases and temperatures. Using scanning transmission electron microscopy (STEM) and energy-dispersive X-ray spectroscopy (EDS), it was shown that titanium reacts with oxygen to form titanium oxide, which has ohmic behavior. In contrast, nickel does not form an ohmic contact despite 600°C thermal treatment. The lower oxygen partial pressure in a nitrogen atmosphere as compared to air results in more oxygen vacancies within the Ga 2 O 3 nanobelts during RTA and a negative threshold voltage shift. A decreased current level after high temperature annealing can be ascribed to significant outward diffusion of oxygen and gallium atoms and to oxidation of the metal electrode. Our results can pave a route to demonstrating high performance β-Ga 2 O 3 nanobelt-based (opto)electronic devices.

Source: ECS Journal of Solid State Science and Technology

DOI: 10.1149/2.0091702jss

Authors: Jinho Bae, Hong-Yeol Kim, Jihyun Kim

Institution: Korea University

Language: English

Topic: Ga2O3 and related materials

Subfield: Electronic, Optical and Magnetic Materials

Field: Materials Science

Domain: Physical Sciences

Open Access status: bronze

Funders: Ministry of Trade, Industry and Energy, Korea Institute of Energy Technology Evaluation and Planning

Awards: G2534848736, G6458345048