N. Esser - Academia.edu (original) (raw)
Papers by N. Esser
Physical Review B, 2001
We apply reflectance anisotropy spectroscopy ͑RAS͒ and low-energy electron diffraction ͑LEED͒ to ... more We apply reflectance anisotropy spectroscopy ͑RAS͒ and low-energy electron diffraction ͑LEED͒ to the study of Sn deposited on a single-domain vicinal Si͑001͒ sample. Large variations in RAS are recorded when up to 5 monolayers ͑ML͒ of Sn is deposited on the Si substrate at room temperature. We observe (2ϫ2) and (1ϫ1) LEED patterns for the 0.5-ML and 1.0-ML Sn covered surfaces, respectively. The (1ϫ1) LEED pattern exists beyond this coverage and up to 5.0-ML deposition. Even though a (1ϫ1) LEED pattern is observed upon deposition of 1.5 ML, surprisingly, a significant optical anisotropy is observed. After annealing to 570°C for 2 min, we observe a progression of LEED pattern changes from c(4ϫ4)→(6ϫ2)→c(8ϫ4) →(5ϫ1) with increased Sn coverage up to 1.5 ML. Similar RAS line shapes are obtained for all reconstructions produced through annealing with the exception of the (5ϫ1). For the (5ϫ1) phase, a significant anisotropy appears in the region of 1.8 eV. Similarities in the RAS line shape for both the (5ϫ1) phase and that obtained after deposition of 1.5 ML of Sn at room temperature may indicate a RAS sensitivity to Sn dimer orientation within the uppermost layer.
Surface Science, 1996
MBE-grown samples capped with a protective Sb layer were used to study clean (100) surfaceS in UH... more MBE-grown samples capped with a protective Sb layer were used to study clean (100) surfaceS in UHV. By thermal desorption of the Sb cap layer GaSb surfaces exhibiting c(2 x 6) reconstruction were prepared, then studied by reflectance anisotropy spectroscopy, low energy electron diffraction and Auger electron spectroscopy. The results of this experimental analysis allowed us to determine for the first time the surface related optical anisotropy of the c(2 x 6) reconstruction of GaSb(100) in the range 1.5-5.5 eV. Reflectance anisotropy spectroscopy features related to optical transitions of surface Sb dimers are identified and discussed. Moreover, the appearance of an optical anisotropy related to the linear electro-optic effect at the E 1 bulk critical point shows the existence of band bending at GaSb decapped surfaces.
Journal of Crystal Growth, 1997
ABSTRACT A new process for chemical passivation of III–V semiconductor surfaces in metalorganic v... more ABSTRACT A new process for chemical passivation of III–V semiconductor surfaces in metalorganic vapour phase epitaxy (MOVPE) is developed. A passivation layer is deposited directly after growth in the reactor. It consists of amorphous arsenic or a double-layer package of amorphous phosphorus and arsenic, which are grown by photo-decomposition of the group-V hydrides. These layers (caps) serve to protect the surfaces against contamination in air after removing the samples from the MOVPE growth reactor. Such passivation is applicable e.g. for a two-step epitaxy or for further surface characterizations.
Applied Surface Science, 1990
The Bi/GaAs(110) interface formation and the growth of the Bi overlayer were investigated in situ... more The Bi/GaAs(110) interface formation and the growth of the Bi overlayer were investigated in situ by Raman spectroscopy, elastic light scattering, and LEED. Additionally, current-voltage (IV) measurements were carried out. Deposition was performed at substrate ...
Applied Physics Letters, 2005
Springer Proceedings in Physics
ABSTRACT
Surface Science, 1994
ABSTRACT
Journal of Vacuum Science & Technology B: Microelectronics Processing and Phenomena, 1987
The Schottky barrier at the InP(110)/Sb interface was determined by Raman scattering for Sb cover... more The Schottky barrier at the InP(110)/Sb interface was determined by Raman scattering for Sb coverages up to 60 monolayers (ML). Band bending variations are found to occur until ∼20 ML. This can be correlated with the Sb structure; from ordered through amorphous to crystalline growth. For higher coverages of Sb the band bending decreases and finally flatband conditions are obtained. This fact is confirmed by I–V measurements at 150 and 400 ML.
physica status solidi (a)
physica status solidi (a), 1998
Have been investigating the physical properties of Cu(110), a surface attained when cutting a sin... more Have been investigating the physical properties of Cu(110), a surface attained when cutting a single copper crystal in a specific direction, for several years. [40]
Materials Chemistry and Physics, 2013
ABSTRACT Optical dielectric functions ε(E) of the (IPA)4Cd3Cl10 crystal were measured in the spec... more ABSTRACT Optical dielectric functions ε(E) of the (IPA)4Cd3Cl10 crystal were measured in the spectral range of fundamental electronic excitations 3.5–10 eV and in the temperature range of 310–400 K containing the phase transition point between the orthorhombic phases Cmce and Pbca. Measurements were performed by spectroscopic ellipsometry with using of synchrotron radiation. Electronic band structure, density of states and dielectric functions ε(E) of (IPA)4Cd3Cl10 were calculated and analyzed on the basis of the density functional theory. Top valence and bottom conduction bands were found to be formed mainly by the cadmium–chlorine complexes of the crystals.
Journal of Crystal Growth, 2001
Copper nitride thin films were deposited on silicon wafers by reactive RF magnetron sputtering at... more Copper nitride thin films were deposited on silicon wafers by reactive RF magnetron sputtering at various N2-gas partial pressures and substrate temperatures. X-ray diffraction measurements show that the films are composed of Cu3N crystallites with anti-ReO3 structure and exhibit preferential orientation to either the [111] or [100] direction at particular N2 pressures and substrate temperatures. The film growth prefers the
Journal of Vacuum Science & Technology B: Microelectronics Processing and Phenomena, 1989
We describe an investigation of an unreactive interface, namely Sb on InP(110) clean cleaved surf... more We describe an investigation of an unreactive interface, namely Sb on InP(110) clean cleaved surfaces. Transport techniques (I–V, C–V), Raman spectroscopy, and soft x-ray photoelectron spectroscopy have been used to study the Schottky barrier heights, overlayer structure, and interface interactions for Sb layers deposited on substrates held at room and low temperatures. The evolution of the overlayer structure at room temperature is complex, with an amorphous Sb layer growing on top of an ordered monolayer, until a thickness of ∼10 monolayers (ML), when the layer crystallizes. The evolution of the Schottky barrier is also complex but for thick layers we observe the lowest barriers on n-InP and the highest ever observed on p-InP. Possible mechanisms for the fact that the Fermi level appears pinned close to the conduction band are discussed.
Physical Review B, 2001
We apply reflectance anisotropy spectroscopy ͑RAS͒ and low-energy electron diffraction ͑LEED͒ to ... more We apply reflectance anisotropy spectroscopy ͑RAS͒ and low-energy electron diffraction ͑LEED͒ to the study of Sn deposited on a single-domain vicinal Si͑001͒ sample. Large variations in RAS are recorded when up to 5 monolayers ͑ML͒ of Sn is deposited on the Si substrate at room temperature. We observe (2ϫ2) and (1ϫ1) LEED patterns for the 0.5-ML and 1.0-ML Sn covered surfaces, respectively. The (1ϫ1) LEED pattern exists beyond this coverage and up to 5.0-ML deposition. Even though a (1ϫ1) LEED pattern is observed upon deposition of 1.5 ML, surprisingly, a significant optical anisotropy is observed. After annealing to 570°C for 2 min, we observe a progression of LEED pattern changes from c(4ϫ4)→(6ϫ2)→c(8ϫ4) →(5ϫ1) with increased Sn coverage up to 1.5 ML. Similar RAS line shapes are obtained for all reconstructions produced through annealing with the exception of the (5ϫ1). For the (5ϫ1) phase, a significant anisotropy appears in the region of 1.8 eV. Similarities in the RAS line shape for both the (5ϫ1) phase and that obtained after deposition of 1.5 ML of Sn at room temperature may indicate a RAS sensitivity to Sn dimer orientation within the uppermost layer.
Surface Science, 1996
MBE-grown samples capped with a protective Sb layer were used to study clean (100) surfaceS in UH... more MBE-grown samples capped with a protective Sb layer were used to study clean (100) surfaceS in UHV. By thermal desorption of the Sb cap layer GaSb surfaces exhibiting c(2 x 6) reconstruction were prepared, then studied by reflectance anisotropy spectroscopy, low energy electron diffraction and Auger electron spectroscopy. The results of this experimental analysis allowed us to determine for the first time the surface related optical anisotropy of the c(2 x 6) reconstruction of GaSb(100) in the range 1.5-5.5 eV. Reflectance anisotropy spectroscopy features related to optical transitions of surface Sb dimers are identified and discussed. Moreover, the appearance of an optical anisotropy related to the linear electro-optic effect at the E 1 bulk critical point shows the existence of band bending at GaSb decapped surfaces.
Journal of Crystal Growth, 1997
ABSTRACT A new process for chemical passivation of III–V semiconductor surfaces in metalorganic v... more ABSTRACT A new process for chemical passivation of III–V semiconductor surfaces in metalorganic vapour phase epitaxy (MOVPE) is developed. A passivation layer is deposited directly after growth in the reactor. It consists of amorphous arsenic or a double-layer package of amorphous phosphorus and arsenic, which are grown by photo-decomposition of the group-V hydrides. These layers (caps) serve to protect the surfaces against contamination in air after removing the samples from the MOVPE growth reactor. Such passivation is applicable e.g. for a two-step epitaxy or for further surface characterizations.
Applied Surface Science, 1990
The Bi/GaAs(110) interface formation and the growth of the Bi overlayer were investigated in situ... more The Bi/GaAs(110) interface formation and the growth of the Bi overlayer were investigated in situ by Raman spectroscopy, elastic light scattering, and LEED. Additionally, current-voltage (IV) measurements were carried out. Deposition was performed at substrate ...
Applied Physics Letters, 2005
Springer Proceedings in Physics
ABSTRACT
Surface Science, 1994
ABSTRACT
Journal of Vacuum Science & Technology B: Microelectronics Processing and Phenomena, 1987
The Schottky barrier at the InP(110)/Sb interface was determined by Raman scattering for Sb cover... more The Schottky barrier at the InP(110)/Sb interface was determined by Raman scattering for Sb coverages up to 60 monolayers (ML). Band bending variations are found to occur until ∼20 ML. This can be correlated with the Sb structure; from ordered through amorphous to crystalline growth. For higher coverages of Sb the band bending decreases and finally flatband conditions are obtained. This fact is confirmed by I–V measurements at 150 and 400 ML.
physica status solidi (a)
physica status solidi (a), 1998
Have been investigating the physical properties of Cu(110), a surface attained when cutting a sin... more Have been investigating the physical properties of Cu(110), a surface attained when cutting a single copper crystal in a specific direction, for several years. [40]
Materials Chemistry and Physics, 2013
ABSTRACT Optical dielectric functions ε(E) of the (IPA)4Cd3Cl10 crystal were measured in the spec... more ABSTRACT Optical dielectric functions ε(E) of the (IPA)4Cd3Cl10 crystal were measured in the spectral range of fundamental electronic excitations 3.5–10 eV and in the temperature range of 310–400 K containing the phase transition point between the orthorhombic phases Cmce and Pbca. Measurements were performed by spectroscopic ellipsometry with using of synchrotron radiation. Electronic band structure, density of states and dielectric functions ε(E) of (IPA)4Cd3Cl10 were calculated and analyzed on the basis of the density functional theory. Top valence and bottom conduction bands were found to be formed mainly by the cadmium–chlorine complexes of the crystals.
Journal of Crystal Growth, 2001
Copper nitride thin films were deposited on silicon wafers by reactive RF magnetron sputtering at... more Copper nitride thin films were deposited on silicon wafers by reactive RF magnetron sputtering at various N2-gas partial pressures and substrate temperatures. X-ray diffraction measurements show that the films are composed of Cu3N crystallites with anti-ReO3 structure and exhibit preferential orientation to either the [111] or [100] direction at particular N2 pressures and substrate temperatures. The film growth prefers the
Journal of Vacuum Science & Technology B: Microelectronics Processing and Phenomena, 1989
We describe an investigation of an unreactive interface, namely Sb on InP(110) clean cleaved surf... more We describe an investigation of an unreactive interface, namely Sb on InP(110) clean cleaved surfaces. Transport techniques (I–V, C–V), Raman spectroscopy, and soft x-ray photoelectron spectroscopy have been used to study the Schottky barrier heights, overlayer structure, and interface interactions for Sb layers deposited on substrates held at room and low temperatures. The evolution of the overlayer structure at room temperature is complex, with an amorphous Sb layer growing on top of an ordered monolayer, until a thickness of ∼10 monolayers (ML), when the layer crystallizes. The evolution of the Schottky barrier is also complex but for thick layers we observe the lowest barriers on n-InP and the highest ever observed on p-InP. Possible mechanisms for the fact that the Fermi level appears pinned close to the conduction band are discussed.