Structural and optical properties of Cr-doped semi-insulating GaN epilayers

Journal Article · Mon Sep 15 04:00:00 EDT 2008 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.2988000· OSTI ID:21175589

Mei, F; Wu, K M; Pan, Y; Han, T; Liu, C ^[1]; Gerlach, J W; Rauschenbach, B ^[2]

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1. Key Laboratory of Acoustic and Photonic Materials and Devices of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072 (China)
2. Leibniz-Institut fuer Oberflaechenmodifizierung, D-04318 Leipzig (Germany)

The properties of Cr-doped GaN epilayers grown by rf-plasma-assisted molecular beam epitaxy were studied. The deep acceptor nature of Cr was used to grow semi-insulating GaN epilayers on sapphire substrates for electronic device applications. The room-temperature (RT) sheet resistivity of the epilayers reached 10{sup 10} {omega}/square. The activation energy of dark conductivity was about 0.48 eV. Step-graded Al{sub x}Ga{sub 1-x}N/GaN (x=0.3-0.2) superlattices (SLs) were designed to filter dislocations. Transmission electron microscopy images showed that the SLs can dramatically reduce dislocation density. Al{sub 0.35}Ga{sub 0.65}N/GaN heterostructure grown on Cr-doped semi-insulating GaN epilayer exhibited a RT mobility of 960 cm{sup 2}/V s and sheet carrier density of 2.1x10{sup 13} cm{sup -2}.

• OSTI ID: 21175589
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 11 Vol. 93; ISSN APPLAB; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ACTIVATION ENERGY
ALUMINIUM NITRIDES
CARRIER DENSITY
CARRIER MOBILITY
CHROMIUM
CRYSTAL GROWTH
DISLOCATIONS
DOPED MATERIALS
ELECTRIC CONDUCTIVITY
ELECTRONIC EQUIPMENT
GALLIUM NITRIDES
HETEROJUNCTIONS
MOLECULAR BEAM EPITAXY
OPTICAL PROPERTIES
SAPPHIRE
SEMICONDUCTOR MATERIALS
SUBSTRATES
SUPERLATTICES
TEMPERATURE RANGE 0273-0400 K
TRANSMISSION ELECTRON MICROSCOPY