Real Space Surface Reconstructions of Decapped As-rich In0.53Ga0.47As(001)-(2×4)

Abstract

The surface reconstructions of decapped In 0.53 Ga 0.47 As(001) have been studied using scanning tunneling microscopy (STM). It is shown that the As-rich 2(2×4) and 2(2×4) reconstructions, predicted by density function theory (DFT) (1-3) for GaAs(001)-(2×4), InAs(001)-(2×4) and InGaAs(001)-(2×4) surfaces, were observed to coexist on In 0.53 Ga 0.47 As (001). In contrast to molecular beam epitaxy (MBE) grown In 0.53 Ga 0.47 As(001), the STM results on decapped In 0.53 Ga 0.47 As(001) do not show the existence of the heterodimer In 0.53 Ga 0.47 As(001)-(4×3) structure (4-5). At the intermediate annealing temperature ranges of 400-440°C, a (2×4)-(4×2) mixed surface reconstruction was observed. When In 0.53 Ga 0.47 As(001)/InP sample was annealed between 440°C and 470°C, a pure In/Ga-rich (4×2) surface reconstruction was observed.

Influence of doping level and surface states in tunneling spectroscopy of an In0.53Ga0.47As quantum well grown on Vergel1, Tadjine2, Notot3 et al. 2019Phys. Rev. Materials6140View full textAdd to dashboardCite

“…The zigzag structure indicates that the smallest protrusions are single As dimers, located either on the left or the right of a row. This reconstruction is typical of the As-rich (2 × 4) structure observed for the In 0.53 Ga 0.47 As (001) surface [15].…”

“…As the temperature used to desorb the As capping layer of an InGaAs (001) surface is known to affect the surface reconstruction [15], arsenic decapping tests were directly done after the deposition of the protective layer and monitored using reflection high-energy electron diffraction (RHEED). In this way, we were able to follow the temperature dependence of the surface reconstruction.…”

Dual Passivation of Intrinsic Defects at the Compound Semiconductor/Oxide Interface Using an Oxidant and a Reductant

“…After the sample was decapped, STM was used to verify that the InGaAs (001)-(2 × 4) surface was free of contaminants (Figure a). The zigzag pattern of the rows in the STM image is due to the presence of two different unit cells on the (2 × 4) surface, the α2-(2 × 4) and the β2-(2 × 4) unit cells . Details of the different unit cells are given in a previous study which has shown that In 0.27 Ga 0.73 As contains 42% missing dimer unit cells and In 0.53 Ga 0.47 As has 78% .…”

“…11 The R2-(2 Â 4) unit cell is missing an AsÀAs dimer on the row, which results in metallic InÀGa bonds. 12 The metalÀmetal bonds directly form valence band (VB) edge states and indirectly induce conduction band (CB) edge Many passivation techniques have been explored for compound semiconductor surfaces, but most rely on external wet cleans, chemicals that are not ideal for introduction into commercial atomic layer deposition (ALD) tools, or temperatures that are not practical. 13À17 Another option would be to avoid the inherent problems of the InGaAs (2 Â 4) surface by using another crystallographic face such as the (110) surface, which is defect-free.…”

“…Edmonds et al showed that GaAs (2 × 4) or InAs (2 × 4) surfaces contain at least 8% α2-(2 × 4) unit cells, and In 0.53 Ga 0.47 As contains 71% α2-(2 × 4) unit cells, which accentuates the need to effectively passivate these defect unit cells . The α2-(2 × 4) unit cell is missing an As–As dimer on the row, which results in metallic In–Ga bonds . The metal–metal bonds directly form valence band (VB) edge states and indirectly induce conduction band (CB) edge states; the metal–metal bonds generate bond angle strain in the edge As atoms which prefer to be in a tetrahedral sp 3 bonding configuration.…”