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About deep impurity centers in InAs

“…3), as in Ge〈Au〉 [19] and InSb [8], the energy of deep impurity states does not depend on hydrostatic pressure. The value of pressure coefficient for the gap between the bottom of the conduction band and the deep impurity level agrees with the pressure coefficient of the width of the forbidden gap [20].…”

“…Pressure (GPa) Figure 3 Energy-spectrum realignment in InAs with deep impurity centers under pressure according to results of the given work and [8,9]. The energy levels of deep acceptor ε a , resonance donor ε d and their pressure coefficients are calculated for 300 K. It was also supposed that the total electron concentrations at the impurity centers n i and in the conduction band n c is a constant:…”

“…As has been noted in [15], we may neglect the widening of deep levels at room temperature. In addition, the influence of chaotic potential intensifies on temperature lowering and decrease of free charge carrier concentration, which may lead to incorrect estimation of pressure coefficients [9,16,17]. Well-known data on the dispersion law, the value of the effective mass of electrons at the bottom of conduction band m c /m 0 , the width of the forbidden gap ε g and the value of the spin-orbital band split Δ S are used in our calculations.…”

“…Let us note once again that in real semiconductor crystals the pressure coefficients of energy gaps, calculated according to well-known dispersion laws, may be overestimated or underestimated because of the intensifying influence of fluctuating potential on the energy spectrum of charge carriers with the temperature decrease and pressure increase, as a result of the inevitable presence of charged impurity centers [16,17]. In [17] it is shown that the hydrostatic pressure is a unique external factor which allows to estimate the influence of the chaotic potential on the energy spectrum of charge carriers and the appropriateness of formulas deduced for a defect-free crystal for the description of defected crystals in very specific case.…”

“…A certain correlation between the pressure coefficient of deep donor centers and the pressure coefficients of Г, L and X valleys relative to the top of the valence band has been found in [6]. On the other hand, the idea of independence of the energy of deep impurity centers from pressure is given proof on the basis of generalization and analysis of experiment results and theory conclusions in [8]. The minor, in the limit of measurement inaccuracy, dependence of electron affinity for deep impurity centers on pressure is conditioned by the fact that their wave functions should extend along all Brillouin zones and the character of the pressure influence on their energy is defined by the evolution of the whole crystal energy spectrum, and not only by the next one or two bands.…”