Point defects on the (110) surfaces ofInP,InAs, andInSb: A comparison with bulk

Abstract

The basic properties of point defects, such as local geometries, positions of charge-transfer levels, and formation energies, have been calculated using density-functional theory, both in the bulk and on the ͑110͒ surface of InP, InAs, and InSb. Based on these results we discuss the electronic properties of bulk and surface defects, defect segregation, and compensation. In comparing the relative stability of the surface and bulk defects, it is found that the native defects generally have higher formation energies in the bulk. From this it can be concluded that at equilibrium there is a considerably larger fraction of defects at the surface and under nonequilibrium conditions defects are expected to segregate to the surface, given sufficient time. In most cases the charge state of a defect changes upon segregation, altering the charge-carrier concentrations. The photothresholds are also calculated for the three semiconductors and are found to be in good agreement with experimental data.

Effect of thermal annealing on electrical and photoelectrical properties of n-InSb

“…Unfortunately, there are very few experimental studies of native defects in bulk crystals and epilayers of InSb [5][6][7][8]. At the same time, comprehensive theoretical investigations were recently published in the literature [9][10][11]. However, when comparing theoretical and experimental data, difficulties arise due to the fact that theoretical calculations were made for the thermal equilibrium conditions, which cannot be entirely realized in the annealing process.…”

Breakdown of cation vacancies into anion vacancy-antisite complexes on III-V semiconductor surfaces

“…6 In that comparison we included the defect formation energy of the cation vacancy at the surface. The structure of that cation vacancy, however, turns out to be more complex than expected.…”

“…For further discussion see Ref. 6.͒ For InSb, InAs, and InP the formation energies of all other native defects, as reported earlier, 6 are also shown in the background as a reference. ͓V A − A C ͔ and V C have an identical dependence on the chemical potential.…”

“…Increasing the slabs to 4 ϫ 4 surface cells has been shown to change the formation energies by less than 0.04 eV. 6 A 2ϫ 2 ϫ 2 Monkhorst-Pack selection was used for the k-point sampling.…”

“…[1][2][3][4][5][6] In contrast to the anion vacancy, there are only a few studies of cation vacancies. In scanning tunneling microscopy ͑STM͒ images of the unoccupied states of GaAs ͑110͒ surfaces, two features interpreted as being caused by Ga vacancies have been reported: Lengel et al 7 observed a dark contrast that appears on an array consisting of about 3 ϫ 3 missing unoccupied dangling bonds, whereas Ebert and Urban 8 and Domke et al 9 observed an X-shaped dark contrast consisting of one missing unoccupied dangling bond.…”