Deep levels related to gallium atom clusters in GaAs

A model for Fermi-level pinning in semiconductors: radiation defects, interface boundaries

“…1 shows the calculated modules of coefficients C a; j nk i at symmetric functions with wave vectors of the ideal crystal, which are equivalent to point G on the super-lattice ðq ¼ 0Þ; and the corresponding modules of the coefficients in model function (2) for deep levels determined by pseudopotential method. With regard to correction for spin-orbital splitting of the valence band, the values of the levels coincide with the results [19][20][21]. As it follows from Fig.…”

“…The sizes of the unit cell were chosen to be ð4 Â 4 Â 4Þ and ð8 Â 8 Â 8Þ as in Refs. [19][20][21]. The function of the defect was represented as expansion of the symmetric combinations of the ideal crystal Bloch functions:…”

Correlation between energy positions of deep intrinsic point-defect levels and a limiting fermi level in irradiated III–V semiconductors

“…The symmetry of localized states is indicated (А 1 and Т 2 are the irreducible representations of a point group of tetrahedron). The energy positions of the deep levels of intrinsic defects are in good agreement with the results of previous calculations for certain semiconductors performed using local pseudopotentials [10,11]. Table 1 also shows the energies Е DL corresponding to the energy positions of the most localized (the deepest) model defect within the limits of semiconductor dielectric gap.…”

“…For GaAs irradiated by electrons, protons, or fast neutrons, this energy position is F lim ≈ E v + 0.6 eV [1], which is close to the theoretical estimations made within the models [3][4][5] and to the values calculated in this work. Moreover, currently available theoretical calculations of the Fermi level position at the cluster/crystal matrix interface (for example, at the Ga As cluster/ GaAs interface) show that in this case, the Fermi level is also pinned near E v + 0.6 eV [18], as it was in the case of point defects in GaAs introduced by electron irradiation. This points to the fact that the Fermi level is always pinned in the proximity of the crystal "neutral" point equal to the energy E av .…”

Deep levels of antisite defects clusters in ZnGeP2

“…The calculation of the deep levels was based on the method of the model pseudopotential [4] with application a large unit cell (LUC). The LUC (3*3*3*) containing 216 atoms was used.…”