Theoretical investigation of the photoluminescence and Fermi surface of periodically delta -doped GaAs

Abstract

A theoretical study of the electronic structure of periodically 6doped GaAs Is presented. When the doping period is reduced, minibends are formed, and the photoluminescence spectrum presents a broad emission band at energies above the GaAs band edge. The experimentally obtained photoluminescence lineshape is well reproduced by the theory. The calculated cut-off energy in the photoluminescence spectrum is in excellent agreement with the experimental value. The Fermi surface is studied as a function of the doping period. The gradual change in the Fermi surface, which occurs when the spacing between the dopant sheets decreases, provides a clear-cut description of the crossover from two-to three-dimensional electronic structure in 6-doped GaAs.The response of the system to a magnetic field, applied in t h e plane of the layers, is considered, and the condition of magnetic breakdown is studied.

Si δ-doping superlattices in InP grown by low-pressure metalorganic vapor phase epitaxy

“…2 is the net charge distribution profile obtained from C-V measurements in sample 187 which has a single &doped layer. The profile shows a FWHM equal to 35w corresponding to an atomic distribution of around 8 A [20], as determined by solving self-consistently the Poisson and Schrodinger equations within the Hartree approximation for the gated delta-doped structure [3,12], once the sheet dopant concentration is known. The dopant localization is used as an input parameter so that the real atomic localization corresponds to the one which gives a theoretical CV profile that best agrees with the experimental one.…”

“…The value of dc is possibly also a function of both the sheet doping concentration [12] and localization. Further investigation is required for a better quantitative understanding of this phenomenon.…”

“…The high energy cut-off, hvCut.,fr, represented by an arrow in Fig. 7 is given by where V is the effective V-shaped potential, E, is the Fermi energy for the conduction miniband measured from the bottom of the V potential and Eh is the Fermi energy for the holes measured from the top of the V potential [11,12,17]. Both E, and Eh should increase with decreasing period, consequently increasing hv,,t-,ff as it is observed in this investigation.…”

“…Such slight discrepancy is positively surprising if one considers that the substitution of N 3 D by N2D/d in Eq. (4) should only be valid for d 5 80 A [12]. The theoretical curve where A is given by the InP bandgap and the coefficient of d-2'3 is calculated using N 2 0 measured by Hall effect is represented in Fig.…”

Topologically protected states in δ -doped junctions with band inversion

“…35 The exchange-correlation potential is usually taken in the approximation of Hedin and Lundqvist 36 and standard self-consistent numerical methods can be then used. [37][38][39][40] However, the nonlinear TF formulation of the δ doping has been proven to be equivalent to the self-consistent (Hartree) model in a wide range of doping densities. [41][42][43][44] The advantage of the TF formulation is that Poisson and Schrödinger equations are effectively decoupled and their solution is easier.…”