Continuous to bound interband transitions in delta-doped GaAs layers (original) (raw)
Related papers
Electronic subband of single Siδ-doped GaAs structures
Superlattices and Microstructures, 2000
We have theoretically investigated the subband structure of single Si δ-doped GaAs inserted into a quantum well at T = 0 K. We will discuss the influence of the δ-doping concentration, the δ-layer thickness and diffusion of donor impurities. The spread of the impurities are taken into account in two different models: (i) a uniform distribution and (ii) a nonuniform distribution. In this paper, the nonuniform distribution is different from the Gaussian distribution use of other authors. The electronic structures have been calculated by solving the Schrödinger and Poisson equations self-consistently. We thus find the confining potential, the subband energies and their eigen envelope functions, the subband occupations and Fermi energy.
Equilibrium Bandstructure of δ-doped Layer in Silicon using
Abstract—Emerging STM technology opens the possibility of creating ultra-high doped silicon devices. For the theoretical analysis of Si: P QW devices, an atomistic tight-binding approach with self-consistent potential calculation is used. Fermi-level, 1Γ, 2Γ and 1∆ bands are of the same order with previous studies. Impurity bands can be simply explained by the band projection of silicon bulk bandstructure.
Using the raw experimental data of Schmid and the known values of band-gap narrowing and Fermi energies for different doping concentrations, the band-to-band and free-carrier absorption coefficients in heavily doped Si are calculated. The behavior of boron-doped Si is different from that of arsenic doped Si. Near threshold, our values of the absorption coefficients are significantly different from those derived by Schmid from the same data. The enhancement of band-to-band transitions due to impurity or free-carrier scattering is not as important in heavily doped Si as in heavily doped Ge. Numerically fitted empirical expressions for the absorption coefficients, suitable for computer simulation studies of opto-electronic devices are given.
Physica B: Condensed Matter, 2003
We have theoretically investigated the electronic structure of two coupled Si d-doped GaAs at T ¼ 0 K. For the uniform donor distribution we have studied the influence of donor concentration on the subband structure. In order to obtain the electronic structure we have calculated self-consistently the Schr. odinger and Poisson equations. From the self-consistent calculation, we have seen that the electronic structure is quite sensitive to the donor concentration and the d-layer separation. Under the assumption that the mobility is limited by the overlap of the wave function and the ionized scattering centers we can estimate that the mobility in single d-doped structures is very low compared to closely spaced coupled d-doped GaAs structures.
Band structure and confined energy levels of the Si[sub 3]N[sub 4]/Si/GaAs system
Journal of Applied Physics, 1997
The band structure of strained Si ͑4-10 ML͒ on ͑001͒ GaAs, band lineups of the strained Si/͑001͒GaAs heterojunction, and confined energy levels of the Si 3 N 4 /Si/GaAs quantum well have been calculated via a pseudopotential method. It has been found that in this technically important Si 3 N 4 /Si/͑001͒GaAs structure, strained Si has a very narrow band gap ͑0.34 eV͒ at the ⌬ Ќ point in the Brillouin zone. For the strained Si/͑001͒GaAs heterojunction, the conduction band offsets from the ⌬ Ќ for Si to the ⌫ valley for GaAs is 0.83 eV, and that from the ⌬ Ќ valley for Si to the X valley for GaAs is 1.21 eV. The valence band offset is 0.25 eV. The lowest confined energy level in the conduction band of the Si 3 N 4 /Si/GaAs quantum well ranging from 4 to 10 monolayers is found to be 0.22-0.28 eV above the conduction band edge of strained Si, or 0.57-0.61 eV below the conduction band edge of GaAs, while the first confined energy level in the valence band is barely above the valence band maximum of GaAs. The accumulation and inversion take place at these confined energy levels.
Equilibrium Bandstructure of ��-doped Layer in Silicon using
Abstract—Emerging STM technology opens the possibility of creating ultra-high doped silicon devices. For the theoretical analysis of Si: P QW devices, an atomistic tight-binding approach with self-consistent potential calculation is used. Fermi-level, 1Γ, 2Γ and 1∆ bands are of the same order with previous studies. Impurity bands can be simply explained by the band projection of silicon bulk bandstructure. The potential profile, in comparison with the single impurity potential, indicates that ionized donors are not only coupled to each other ...
The self-consistent calculation of Si δ-doped GaAs structures
Applied Physics A: Materials Science & Processing, 2001
In this study, we report results of a self-consistent calculation obtained for the sub-band structure of Si δdoped GaAs material by using a new alternative method. We will discuss the influence of the δ-doping concentration and the δ-layer thickness on the sub-band structure for a non-uniform distribution, which is taken as different from the known Gaussian distribution. The confining potential, the sub-band energies, the sub-band occupations, and the Fermi energy have been calculated by solving the Schrödinger and Poisson equations by using the Airy functions self-consistently.
Electronic properties of two coupled Si δ -doped GaAs structures
The European Physical Journal Applied Physics, 2003
We have theoretically investigated the subband structure of two coupled Si δ-doped GaAs at T = 0 K. For the uniform distribution we have studied the influence of the separation between the two doping layers. The electronic properties such as the effective potential, the density profile, the subband energies, the subband populations and Fermi energy have been calculated by solving Schrödinger and Poisson equations self-consistently. In this study, we have seen that the subband structure is quite sensitive to the separation between the two doping layers. We conclude that, if the coupling between two δdoped GaAs layers is significant, the mobility of electrons in this structure is very high compared to single δ-doped structures because of the strong overlap between the electrons and the ionized donors in single δ-doped structures. PACS. 73.90.+f Other topics in electronic structure and electrical properties of surfaces, interfaces, thin films, and low-dimensional structures
Electronic properties of Si δ-doped GaAs under an applied electric field
Semiconductor Science and Technology, 2001
We have theoretically investigated the electronic structure of Si δ-doped GaAs inserted into a quantum well under an applied electric field. For uniform distribution we have studied the influence of the electric field on the donor concentration. The electronic properties such as the effective potential, the density profile, the subband energies, the subband occupations and the Fermi energy level have been calculated by solving the Schrödinger and Poisson equations self-consistently. From our calculations, we have seen that the change of the electronic properties as dependent on the applied electric field is more pronounced at low doping concentration. The high electric fields can induce a spatial separation between confined electrons and ionized dopants in the δ-doped GaAs structure, resulting in enhanced free-carrier mobility in devices.