Analysis of the shallow and deep center occupancies in silicon-doped aluminum gallium arsenide using a multilevel donor model

The concentration of occupied deep centers in Si-doped AlxGa1-xAs for x=0.2 has been calculated from a three-level donor model, in which the shallow levels are treated as excited states of the deep (DX) ground state. The deep level is assumed to be tied to the L valley, and the shallow levels to the G and X valleys. The behavior of the free-electron density and the thermal activation energy as function of composition is in good agreement with experimental results reported in the literature. In this model of dependent donor levels the deep-level occupancy can be directly calculated without needing deep-level transient spectroscopy measurements. A two-level donor model is used to calculate the pressure dependence of the deep level from a hydrostatic pressure experiment on a GaAs/Al0.3Ga0.7As heterostructure reported in the literature. We assume a shallow level tied to the G valley and an arbitrary deep level which is not coupled to any of the conduction bands. The calculation of the position of the deep level relative to the G valley as a function of pressure confirms the coupling of the deep level to the L valley. In this dependent donor model no large compensation is needed to fit the experimental data

Temperature dependence of electron concentration in cadmium arsenide

From measurements of the temperature dependence of the electron concentration in Cd 3 As 2 , we found values for the conduction-band parameters that are in good agreement with those recently reported by Aubin, Caron, and Jay-Gerin. However, in contrast with these authors we found no small overlap, but a relatively large gap of 26 meV between the heavy-hole band maximum and the conduction-band minimum

Subband population and electron subband mobility for two interacting Si-δ-doping layers in GaAs

Contains fulltext : 112798.pdf (publisher's version ) (Open Access

Analysis of the shallow and deep center occupancies in silicon-doped aluminum gallium arsenide using a multilevel donor model

The concentration of occupied deep centers in Si-doped AlxGa1-xAs for x=0.2 has been calculated from a three-level donor model, in which the shallow levels are treated as excited states of the deep (DX) ground state. The deep level is assumed to be tied to the L valley, and the shallow levels to the G and X valleys. The behavior of the free-electron density and the thermal activation energy as function of composition is in good agreement with experimental results reported in the literature. In this model of dependent donor levels the deep-level occupancy can be directly calculated without needing deep-level transient spectroscopy measurements. A two-level donor model is used to calculate the pressure dependence of the deep level from a hydrostatic pressure experiment on a GaAs/Al0.3Ga0.7As heterostructure reported in the literature. We assume a shallow level tied to the G valley and an arbitrary deep level which is not coupled to any of the conduction bands. The calculation of the position of the deep level relative to the G valley as a function of pressure confirms the coupling of the deep level to the L valley. In this dependent donor model no large compensation is needed to fit the experimental data

Inversion asymmetry spin level splitting in zero-gap semimagnetic semiconductors

We present a new model to interpret recent measurements on Hg1-xMnxSe which show an angular dependence of the nodes in the Shubnikov-de Haas amplitude. The model is based on an infinite Hamiltonian matrix including inversion asymmetry terms. We additionally took into account the exchange interaction, typical for Semimagnetic Semiconductors. By truncating the matrix we can calculate the electron energy levels, allowing us to describe the experimentally observed nodal field positions

Optical verification of the valence band structure of cadmium arsenide

Optical absorption measurements were performed on thin single crystalline samples of Cd3As2 at temperatures of 300 K and 10 K. At low temperature the interband absorption coefficient shows clearly two steps due to direct transitions from the heavy hole and light hole valence bands to the conduction band. The absorption coefficient can be interpreted quantitatively in an isotropic inverted Kane band model with a modified heavy hole band with its maximum shifted from the ?-point

Quantum- and transport electron mobility in the individual subbands of a two-dimensional electron gas in Si-δ-doped GaAs

Contains fulltext : 112809.pdf (publisher's version ) (Open Access