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

• Main Authors: Sadia, Cyril P., Laganapan, Aleena Maria, Tumanguil, Mae Agatha, Estacio, Elmer, Somintac, Armando, Salvador, Arnel A., Que, Christopher T., Yamamoto, Kohji, Tani, Masahiko
• Format: text
• Published: Animo Repository 2012
• Subjects: Gallium arsenide; Indium arsenide; Molecular beam epitaxy; Scanning electron microscopy; Electric fields; Physics
• Online Access: https://animorepository.dlsu.edu.ph/faculty_research/3744; https://animorepository.dlsu.edu.ph/context/faculty_research/article/4746/type/native/viewcontent/1.4770267
• Institution: De La Salle University

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.