Infrared dielectric functions, phonon modes, and free-charge carrier properties of high-Al-content AlxGa1-xN alloys determined by mid infrared spectroscopic ellipsometry and optical Hall effectShow others and affiliations
2017 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 121, no 20, article id 205701Article in journal (Refereed) Published
Abstract [en]
We report on the analysis of a combined mid-infrared spectroscopic ellipsometry and mid-infrared optical Hall effect investigation of wurtzite structure c-plane oriented, crack-free, single crystalline, and high-Al-content AlxGa1-xN layers on 4H-SiC. For high-Al-content AlxGa1-xN, a two mode behavior is observed for both transverse and longitudinal branches of the infrared-active modes with E-1 symmetry, while a single mode behavior is found for the longitudinal modes with A1(LO) symmetry. We report their mode dependencies on the Al content. We determine and discuss static and high frequency dielectric constants depending on x. From the analysis of the optical Hall effect data, we determine the effective mass parameter in high-Al-content AlxGa1-xN alloys and its composition dependence. Within the experimental uncertainty limits, the effective mass parameters are found isotropic, which depend linearly on the Al content. The combination of all data permits the quantification of the free electron density N and mobility parameters mu. Published by AIP Publishing.
Place, publisher, year, edition, pages
AMER INST PHYSICS , 2017. Vol. 121, no 20, article id 205701
National Category
Other Materials Engineering
Identifiers
URN: urn:nbn:se:liu:diva-139410DOI: 10.1063/1.4983765ISI: 000404164200006OAI: oai:DiVA.org:liu-139410DiVA, id: diva2:1129879
Note
Funding Agencies|Swedish Research Council (VR) [2013-5580, 2016-00889]; Swedish Governmental Agency for Innovation Systems (VINNOVA) under the VINNMER international qualification program [2011-03486]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University, Faculty Grant SFO Mat LiU [2009 00971]; Swedish Foundation for Strategic Research (SSF) [FFL12-0181, RIF14-055]; National Science Foundation [MRSEC DMR-0820521, MRI DMR-0922937, DMR-0907475, EPS-1004094]; [VR 621-2013-5818]; [VINNOVA 2011-01329]
2017-08-072017-08-072024-03-01