Hyperbolic-tan graded composition InxGa1-xAs layers for THz radiation emitters

•Metamorphic InGaAs graded layers have been grown varying the In mole fraction.•Strain driven dislocations reactions during annealing improve the crystal quality of graded layers.•Energy band bending due to hyperbolic-tan profiles accelerates free carriers improving THz emission.•New research line t...

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Bibliographic Details
Published in:Journal of crystal growth 2022-07, Vol.589, p.126680, Article 126680
Main Authors: Belio-Manzano, A., Regalado-de la Rosa, J.L., Mercado-Ornelas, C.A., Cortes-Mestizo, I.E., Espinosa-Vega, L.I., Alanis, Javier, Castro-Camus, E., Valdez-Pérez, Donato, Kudriavtsev, Yu, Méndez-Garcia, V.H.
Format: Article
Language:English
Subjects:
A1. Graded composition
A1. Strain
B1. Gallium compounds
B3. THz emitters
Bending
Composition
Electric fields
Emission analysis
Emitters
Indium gallium arsenides
Laser pumping
Molecular beams
Substrates
Ternary alloys
Thickness
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Summary:•Metamorphic InGaAs graded layers have been grown varying the In mole fraction.•Strain driven dislocations reactions during annealing improve the crystal quality of graded layers.•Energy band bending due to hyperbolic-tan profiles accelerates free carriers improving THz emission.•New research line throughout near-surface band bending is envisioned for THz applications. The growth and characterization of InxGa1-xAs layers with hyperbolic tangent In concentration profiles is presented. Along the growth the molecular beam fluxes of Ga and In, and the substrate temperature were varied. Since the concentration of In is varied during growth process the strain is expected to increase monotonically, and eventually be relaxed via dislocation formation. Positively, reordering of the ternary alloy and the improvement of its crystal quality were propitiated by annealing the samples. The gradual In concentration propitiated along the thickness of the film conduced to variations of the near-surface band bending. The THz emission from GaAs, InAs, and graded samples was investigated by femtosecond laser pumping excitation. The band-bending from hyperbolic-tan graded composition InxGa1-xAs layers causes depth dependence of effective mass and built-in electric fields modifying accordingly the THz emission.
ISSN:0022-0248
1873-5002
DOI:10.1016/j.jcrysgro.2022.126680