Large negative magnetoresistance induced by interplay between smooth disorder and antidots in AlGaN/GaN HEMT structures

Mishra, MK and Sharma, RK and Tyagi, R and Manchanda, R and Pandey, AK and Thakur, OP and Muralidharan, R (2016) Large negative magnetoresistance induced by interplay between smooth disorder and antidots in AlGaN/GaN HEMT structures. In: MATERIALS RESEARCH EXPRESS, 3 (4).

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Abstract

Large low temperature negative magnetoresistance (NMR) experimentally observed in AlGaN/GaN high electron mobility transistors (HEMT) structures grown by metalorganic chemical vapour deposition on sapphire substrate has been reported. A linear B-1 ln B dependence of magnetoresistance observed in our samples indicates the presence of random antidot array together with smooth disorder. It is proposed that the antidots are linked with high bandgap AlN rich regions formed due to possible Al-Ga segregation at the interface during growth and the smooth random disorder is due to interface roughness. The antidot density is estimated to be of similar to 7 to 8 x 10(10) cm(-2) in our samples. The magnitude ofNMRis also correlated with the extent of interface roughness indicated by x-ray reflectivity. It is also proposed that the formation of antidots is related with the lattice mismatch between substrate and epitaxial heterostructures. The NMR in AlGaN/GaN HEMT structures grown on SiC substrates having relatively lower lattice mismatch has been shown to have a usual B-2 and ln T dependences indicating only electron-electron interaction and absence of antidot-like scatterers.

Item Type:	Journal Article
Publication:	MATERIALS RESEARCH EXPRESS
Publisher:	IOP PUBLISHING LTD
Additional Information:	Copy right for this article belongs to the IOP PUBLISHING LTD, TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND
Keywords:	AlGaN/GaN HEMT; magnetotransport; Shubnikov de Haas oscillations
Department/Centre:	Division of Interdisciplinary Sciences > Centre for Nano Science and Engineering
Date Deposited:	19 Jul 2016 10:11
Last Modified:	19 Jul 2016 10:11
URI:	http://eprints.iisc.ac.in/id/eprint/54209

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