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

abstract

  • 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. © 2022 Elsevier B.V.

publication date

  • 2022-01-01