Terahertz gain on inter-valence-band transitions in multilayer delta-doped p-GaAs structures

Abstract

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Inter-Valence-Band Hot Hole Laser in Two-Dimensional Delta-Doped Homoepitaxial Semiconductor Structures

“…For GaAs grown by vapor phase epitaxy, the thickness might even approach 1 mm. 27 In order to consider the effects of the Figure 5 design and the dependence of its performance on geometry, temperature, and doping, we calculate gain from hothole distribution functions simulated by the Monte-Carlo method. 17 In this method, we compute hole trajectories in crossed E and B fields while keeping track of hole energy, position, and the space-charge distribution.…”

“…We recently completed calculations on GaAs deltadoped structures. 27 Ge and GaAs have nearly the same optical phonon energy, but a critical difference between them is the polar optical phonon scattering in GaAs, which provides a "hard ceiling" for hot holes in this material. When holes emit optical phonons at energies close to the optical phonon threshold, they return very near to k = 0.…”

“…To consider the sum total of all effects, we first compare in Figure 11 the calculated gain spectra in bulk unstructured p-GaAs 27 and p-Ge. 29 The raw gain is indeed found to be larger for GaAs at low frequencies.…”

“…This is partially explained by the comparatively severe effects of impurity scattering in GaAs, which limit the optimum carrier concentration in the structure to a value little more than that optimum for bulk. 27 (In Ge, the optimum concentration for the structure was 5 times higher than for bulk). Thus, the only advantage of GaAs over Ge might be technological, whereby certain growth techniques such Wavenumber (cm -1 ) Fig.…”

“…[29]) and p-GaAs (lower, from Ref. [27]). Losses due to absorption by acoustic phonons are not included.…”