Intense terahertz emission from molecular beam epitaxy-grown GaAs/GaSb(001)

College

College of Science

Department/Unit

Physics

Document Type

Article

Source Title

Journal of Applied Physics

Volume

112

Issue

12

Publication Date

12-1-2012

Abstract

Intense terahertz (THz) electromagnetic wave emission was observed in undoped GaAs thin films deposited on (100) n-GaSb substrates via molecular beam epitaxy. GaAs/n-GaSb heterostructures were found to be viable THz sources having signal amplitude 75% that of bulk p-InAs. The GaAs films were grown by interruption method during the growth initiation and using various metamorphic buffer layers. Reciprocal space maps revealed that the GaAs epilayers are tensile relaxed. Defects at the i-GaAs/n-GaSb interface were confirmed by scanning electron microscope images. Band calculations were performed to infer the depletion region and electric field at the i-GaAs/n-GaSb and the air-GaAs interfaces. However, the resulting band calculations were found to be insufficient to explain the THz emission. The enhanced THz emission is currently attributed to a piezoelectric field induced by incoherent strain and defects. © 2012 American Institute of Physics.

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Digitial Object Identifier (DOI)

10.1063/1.4770267

Disciplines

Physics

Keywords

Gallium arsenide; Indium arsenide; Molecular beam epitaxy; Scanning electron microscopy; Electric fields

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