Showing papers on "Band offset published in 1999"
TL;DR: In this article, the critical thickness at which the oxidation rate switches from being limited by chemical kinetics to being diffusion limited is estimated, and a novel method is introduced to evaluate the band offset within local orbital density functional theory.
Abstract: The local atomic structure of ultrathin gate oxides and its effect and that of the corresponding ${\mathrm{SiO}}_{2}\ensuremath{-}\mathrm{Si}$ interface on the band offset of a MOS structure are investigated theoretically. To generate a physically realistic interface, we perform a ``direct oxidation'' simulation using quantum molecular dynamics. The critical thickness at which the oxidation rate switches from being limited by chemical kinetics to being diffusion limited is estimated. A novel method is introduced to evaluate the band offset within local orbital density functional theory. The valence band offset for the ultrathin oxide is found to be smaller (by 0.3 eV) than that of oxides thicker than $\ensuremath{\sim}10\AA{}$ in accord with the recent XPS results.
87 citations
TL;DR: In this article, the authors used X-ray photoelectron spectroscopy (XPS) to measure the energy discontinuity in the valence band (ΔEv) of Ga1-xNxAs/AlAs and estimated ΔEv of GaNAs/GaAs by using the Al2p energy level as a reference.
Abstract: We used X-ray photoelectron spectroscopy (XPS) to measure the energy discontinuity in the valence band (ΔEv) of Ga1-xNxAs/AlAs (x=0, 0.014, 0.034) and estimated ΔEv of GaNAs/GaAs by using the Al2p energy level as a reference. The change in ΔEv for GaNAs/GaAs with an increasing nitrogen content was -(0.019±0.053) eV/%N. This suggests that the valence-band edge (Ev) in GaNAs decreases in proportion to the nitrogen content. Based on the decrease in the bandgap energy of GaNAs, we found that the energy discontinuity in the conduction band (ΔEc) of GaNAs/GaAs is -(0.175±0.053) eV/%N. This large effect of bandgap bowing on the conduction band indicates that an ideal carrier confinement in the well can be obtained by using GaInNAs as an active layer in long-wavelength laser diodes.
76 citations
TL;DR: In this article, the optical properties of nanoscale InAs quantum dots (QDs) in a Si matrix were investigated and it was shown that 7 ML InAs leads to the formation of coherent islands with dimensions in the 2-4 nm range.
Abstract: We investigate the optical properties of nanoscale InAs quantum dots (QDs) in a Si matrix. At a growth temperature of 400 °C, the deposition of 7 ML InAs leads to the formation of coherent islands with dimensions in the 2–4 nm range. A luminescence band in the 1.3 μm region found exclusively for samples with such InAs QDs exhibits a pronounced excitation density dependence of the peak position and a decay time of 440 ns. The optical properties suggest an indirect type II transition for InAs/Si QDs. The electronic structure of InAs/Si QDs is discussed in view of available band offset information.
64 citations
TL;DR: In this paper, the energy shifts of the lowest conduction band and the uppermost valence band were calculated for n-type 3 C-, 2H-, 4H-, 6H-SiC, and SiC.
Abstract: Doping-induced energy shifts of the lowest conduction band and the uppermost valence band have been calculated for n-type 3 C-, 2H-, 4H-, 6H-SiC, and Si. We present the resulting narrowing of the f ...
55 citations
TL;DR: In this article, the conduction band offset of the type II heterostructure CdS/ZnSe was determined from photoluminescence data of single quantum wells, which were grown by compound-source molecular-beam epitaxy.
Abstract: The conduction band offset of the type II heterostructure CdS/ZnSe is determined from photoluminescence data of single quantum wells. The cubic quantum well samples have been grown by compound-source molecular-beam epitaxy. Photoluminescence spectra were measured at low temperatures and evaluated by fitting an effective mass model to the transition energies. A conduction band offset of (0.80±0.1) eV and an effective electron mass for cubic CdS of (0.18±0.05)m0 were determined.
54 citations
TL;DR: In this paper, a quantum well composed of layered semiconductors and SnSe2 (Eg=1.03 eV) and SnS2 (eg=2.18 eV) was grown in several steps by van der Waals epitaxy.
Abstract: A quantum well composed of layered semiconductors and SnSe2 (Eg=1.03 eV) and SnS2 (Eg=2.18 eV) was grown in several steps by van der Waals epitaxy. After each growth step the electronic structure was characterized by ultraviolet and x-ray photoemission spectroscopy. From these measurements, bandbending and the valence-band offset were determined on both sides of the quantum well. The results show that both wells are of the same magnitude, hence indicating commutativity of the band offset. Small interface dipoles (0.11–0.19 eV) were detected at the interfaces, which could be identified as quantum dipoles.
48 citations
TL;DR: In this article, the Schrodinger and Poisson's equations were used to calculate the conduction band profile, energy levels, and Fermi energy of negatively charged semiconductor quantum dots.
Abstract: The three-dimensional Schrodinger and Poisson’s equations are used to calculate the conduction band profile, energy levels, and Fermi energy of negatively charged semiconductor quantum dots. The calculation is carried out self-consistently within the frame of the finite-difference method. Assuming the effective mass of the proton at the semiconductor–electrolyte interface, we found the conduction band profile for the spherical ZnO quantum dots dispersed as aqueous colloids very similar to the conduction band profile of symmetric modulation-doped semiconductor quantum wells. The energy levels and Fermi energy of the spherical ZnO quantum dots are obtained as a function of the band offset at the semiconductor–electrolyte interface. A comparison of the energy levels for negatively charged and uncharged quantum dots is used as an alternative explanation of the observed reversible blue shift in the absorption spectrum of semiconductor colloids under illumination.
44 citations
TL;DR: In this paper, the optical properties of GaInNAs/GaAs grown by chemical beam epitaxy (CBE) using a radical nitrogen source were investigated by measuring of optical absorption spectra.
41 citations
TL;DR: In this article, angle-dependent UPS measurements at two different photon energies demonstrate that the dispersion of the valence band (VB) must be checked carefully in order to find the true position of the VB maximum in the Brillouin zone.
Abstract: We have investigated the valence band offset (ΔE VBO ) of the molecular beam epitaxially grown heterostructure HgTe/CdTe(001) by k-resolved ultraviolet (UPS) and X-ray (XPS) photoemission. Our angle-dependent UPS measurements at two different photon energies demonstrate that the dispersion of the valence band (VB) must be checked carefully in order to find the true position of the VB maximum in the Brillouin zone. With this information the valence band discontinuity was determined as (0.53 ± 0.03) eV, which is different from previously found photoemission values but now agrees well with magneto-optical investigations. In addition, we have determined the energy gap of CdTe(001) and HgTe(001) by a combination of UV and inverse photoemission. The energy gap of CdTe is determined to (1.57 ± 0.06) eV and that for HgTe as (0.0 ± 0.06) eV. We therefore conclude that HgTe is a semi-metal with inverted band structure in agreement with other results.
28 citations
TL;DR: In this paper, the formation of the ZnSe/CuGaSe heterointerface was studied by x-ray photoelectron spectroscopy (XPS), and a nearly symmetric "type-I" band alignment with a conduction-band offset of ΔEC=0.4±0.1
Abstract: The formation of the ZnSe/CuGaSe₂ heterointerface was studied by x-ray photoelectron spectroscopy (XPS). ZnSe was sequentially grown on CuGaSe₂(001) epilayers. In situ photoemission spectra of the Ga 3d and Zn 3d core levels as well as XPS valence bands were acquired after each deposition step. The valence-band offset is determined to be ΔEV=0.6±0.1 eV. As a consequence, a nearly symmetric "type-I" band alignment for the ZnSe/CuGaSe₂ heterojunction with a conduction-band offset of ΔEC=0.4±0.1 eV is found. Concerning the band alignment ZnSe can, therefore, be expected to be a suitable buffer material for CuGaSe₂-based thin-film solar cells.
26 citations
TL;DR: In this article, the coupling between two ultrathin InAs layers embedded in a GaAs matrix was used to determine the band offsets at a highly strained InAs/GaAs interface.
Abstract: We have experimentally determined the band offsets at a highly strained InAs/GaAs interface by means of coupling between two ultrathin InAs layers embedded in a GaAs matrix. When both InAs layers are separated by a 32-ML barrier, the confined electron and light-hole~lh! states are split into symmetric and antisymmetric states, whereas the heavy-hole ~hh! level is not split yet. Consequently, the splitting between the hh exciton transitions, which is measured by photoluminescence excitation spectroscopy, is solely determined by the conduction-band offset DEc . Knowing DEc , the hh and lh band offsets DEhh and DElh were subsequently determined from the coupling-induced shift and splitting in samples with 16-, 8-, and 4-ML barriers. We find a conduction-band offset of 535 meV, a conduction-band offset ratio of Qc50.58, and a strain-induced splitting between the hh and lh levels of 160 meV. This method for the direct determination of band offsets is explicitly sensitive to the band-offset ratio, and its application is not restricted to particular type-I semiconductor heterostructures as long as the effective-mass‐band-offset product for the conduction and valence bands differs by at least a factor of 2. @S0163-1829~99!01715-4#
TL;DR: In this paper, the authors identify three aspects of the chemical bonding at Si-dielectric interfaces that play crucial roles in the implementation of alternative gate dielectrics for advanced CMOS Si devices.
TL;DR: In this article, the properties of diamond/amorphous carbon heterostructures were studied using photoelectron spectroscopy in the ultraviolet (UPS) and x-ray (XPS) regime.
Abstract: In this paper the properties of diamond/amorphous carbon heterostructures are studied using photoelectron spectroscopy in the ultraviolet (UPS) and x-ray (XPS) regime. The nondiamond carbon films are deposited on a p-doped polycrystalline diamond substrate, and produced by first, electron beam evaporation of graphite forming hydrogen-free amorphous carbon $(a\ensuremath{-}\mathrm{C}:\mathrm{H})$ films. The overlayer formation is monitored step-by-step, and the changes in band bending in the diamond substrate and the valence band discontinuities are deduced from the UPS and XPS spectra. In the $\mathrm{diamond}/a$-C structure a downward band bending in diamond evolves continuously with overlayer thickness and a final value of about 1.1 eV is obtained, resulting in a band offset of $1.5\ifmmode\pm\else\textpm\fi{}0.1\mathrm{eV}.$ In the $\mathrm{diamond}/a\ensuremath{-}\mathrm{C}:\mathrm{H}$ structure a downward band bending of 1.4 eV is observed after only a brief deposition time, when the estimated overlayer thickness is still less than a monolayer. The ion energies employed for the film deposition were 200 and 600 eV and although the resulting overlayers exhibit characteristic structural differences, the band bending and band offset $(1.4\ifmmode\pm\else\textpm\fi{}0.15\mathrm{eV})$ are not noticeably influenced. It appears likely that in this case the defects formed in the diamond lattice through the energetic ions used for the overlayer deposition, are responsible for a pinning of the Fermi level at the surface. In an additional experiment the diamond substrate was irradiated with ${\mathrm{Ar}}^{+}$ ions (3 keV) and the resulting band bending, induced through the creation of a defect-rich surface layer, amounts to about 1.3 eV. The introduction of dangling bonds and/or \ensuremath{\pi}-bonded regions, which are energetically located in the gap of diamond, leads to the observed increase in downward band bending in the p-doped diamond.
TL;DR: In this paper, the authors examined the impact of bandgap offset distribution between conduction and valence bands in Si-based graded bandgap HBT's using dc and ac simulation.
Abstract: This work examines the impact of bandgap offset distribution between conduction and valence bands in Si-based graded bandgap HBT's using dc and ac simulation. For a fixed total bandgap offset, a conduction band pushed up by the total offset, together with a valence band pushed up by 2× the total offset gives the best ac performance, and allows the highest operational current for high frequency applications in an n–p–n HBT. A retrograded mole fraction profile, when properly optimized, can produce nearly identical ac performance for different bandgap offset distributions. These suggest that contrary to popular belief, applying careful optimization can yield excellent transistor performance for any arbitrary band alignment for both n–p–n and p–n–p graded bandgap HBT's.
TL;DR: In this paper, a series of Al0.4Ga0.6Sb/GaSb single quantum well, with well thicknesses ranging from 40 to 117 A, by reflectance R and photoreflectance PR, were studied in the 0.6 to 1.5 eV spectral range and at temperatures from 6 to 300 K.
Abstract: Despite the recent upsurge in research on GaSb-based systems, only few systematic investigations have been performed on the fundamental optical and electronic properties of AlxGa1xSb/GaSb quantum wells. For this reason we studied a series of Al0.4Ga0.6Sb/GaSb single quantum wells, with well thicknesses ranging from 40 to 117 A, by reflectance R and photoreflectance PR in the 0.6 to 1.5 eV spectral range and at temperatures from 6 to 300 K. The structures were grown by molecular-beam epitaxy on 001 GaSb substrates and structurally and compositionally characterized by photoluminescence, x-ray diffraction, and reflection highenergy electron diffraction. Both R and PR spectra showed clear evidence of the structures associated with the transitions allowed between the nth heavy-light- hole subband and the nth conduction subband for n1 and 2. Standard critical-point line shapes fitted satisfactorily the PR structures, allowing accurate determination of both transition energies and broadening parameters as functions of the well thickness. The transition energies were well fitted by a theoretical model based on the envelope-function scheme, thus giving reliable values for the two fit parameters, i.e., the band offset and the conduction-band nonparabolicity. S0163-18299905423-5
TL;DR: Semiconductor alloy heterojunctions, with compositions selected to achieve small band offset energies, were used in distributed Bragg reflector (DBR) structures for the purpose of lowering the vertical series resistance.
Abstract: Semiconductor alloy heterojunctions, with compositions selected to achieve small band offset energies, were used in distributed Bragg reflector (DBR) structures for the purpose of lowering the vertical series resistance The heterojunctions were simple abrupt interfaces without composition grading 40 period mirrors of AlGaInP/Al(Ga)As layer pairs were grown by gas-source molecular beam epitaxy Mirror reflectance values were found to be greater than 99% at wavelengths near 650 nm Measured specific resistance values, 28×10−4 Ω cm2 for a p-type DBR and 26×10−5 Ω cm2 for a n-type DBR, were comparable to or better than (Al)GaAs/Al(Ga)As DBRs employing various graded interface composition designs
TL;DR: In this paper, a first-principles scalar relativistic version of fullpotential self-consistent linear muffin tin orbital (LMTO) method, together with a density functional theory in local density approximation, has been employed for calculating the electronic structure of the superlattices formed from two different types of semiconductors.
TL;DR: In this article, the authors report high-pressure photoluminescence (PL) experiments on GaInP/AlGaInP laser structures and a comprehensive interpretation of the results via calculations based on the Model Solid Theory (MST) of Van de Walle et al.
Abstract: We report high-pressure photoluminescence (PL) experiments on GaInP/AlGaInP laser structures and a comprehensive interpretation of the results via calculations based on the Model Solid Theory (MST) of Van de Walle et al. [1, 2]. This methodology allows an accurate description of the band structure and band offsets in complex heterostructures over a wide range of sample compositions and applied pressures. Measurements are performed on Ga 0.4 In 0.6 P/(Al 0.6 Ga 0.4 ) 0.5 In 0.5 P (nominal compositions) double heterojunction samples having active layers of either 125 or 30 A. The pressure data determine a reliable set of deformation potentials for the three constituent binary compounds in this system, InP, AlP and GaP. Using these deformation potentials and a realistic equation of state, the MST calculation gives a reasonable representation of the observed PL spectra over the full presure range (0 to 5 GPa) studied. The conduction band offset ΔE c , valence band offset ΔE v , and the bulk bandgap energies are computed in this materials system for a wide variety of conditions. At ambient pressure we find ΔE c : ΔE v 70: 30, in accord with the consensus value of the band-offset ratio in similar heterostructures. However, our calculations predict band-offset variations with both composition and applied pressure that are non-negligible.
TL;DR: In this article, a tensile strain on both the well and the barrier and compensating for them with a compressive strained intrinsic layer was proposed to overcome the disadvantages of a low conduction band offset and a high heavy-hole band offset.
Abstract: In a conventional polarization-insensitive multiquantum-well electroabsorption modulator, it is normal to apply tensile and compressive strain on the well and the barrier, respectively. But the main disadvantages of such a structure are a low conduction band offset (0.04-0.06 eV), a high heavy-hole band offset (0.20-0.24 eV), and a relatively large well thickness (110-120 /spl Aring/). We propose a new method of overcoming these disadvantages by placing a tensile strain on both the well and the barrier and compensating for them with a compressive strained intrinsic layer.
TL;DR: In this paper, the authors reformulated the tight-binding approach in terms of quantum defects so that band offsets could be calculated from the measured atomic spectroscopic term values, and the calculated band offsets were found to be in reasonable agreement with experiment for a number of existing heterojunctions.
Abstract: In a tight-binding approach, the band offset involves the valence band maxima and hybrid energy; and previously, these have been calculated from first-principles Hartree–Fock method. Here, we reformulate the tight-binding approach in terms of quantum defects so that band offsets could be calculated from the measured atomic spectroscopic term values. As a result, the calculated band offsets are found to be in reasonable agreement with experiment for a number of existing heterojunctions.
TL;DR: In this article, a first principles scalar relativistic version of full potential self-consistent linear muffin tin orbital (LMTO) method, together with a local density functional theory, has been employed for calculating the electronic structure and the atomic structures of the superlattices formed from the two different types of semiconductors.
TL;DR: In this paper, the conduction-band offset ratio was estimated to be 0.75±0.10 for the Al0.66In0.34As0.84Sb0.15/Ga0.64In 0.36As 0.
Abstract: We have grown unstrained Al0.66In0.34As0.85Sb0.15/Ga0.64In0.36As0.84Sb0.16 multiple-quantum-well (MQW) structures on InP substrates by metalorganic vapor phase epitaxy. Low-temperature photoluminescence was performed for these MQW structures. By comparing the luminescence peak energies with the theoretical calculations, we estimated the conduction-band offset ratio to be 0.75±0.10 for the Al0.66In0.34As0.85Sb0.15/Ga0.64In0.36As0.84Sb0.16 heterostructure.
TL;DR: In this paper, chemical bonding effects at Si-dielectric interfaces are discussed for the implementation of alternative gate dielectrics including: i) the character of interfacial bonds, either isovalent with bond and nuclear charge balanced as in Si-SiO2, or heterovalent, with an inherent mismatch between bond and charge, and ii) mechanical bonding constraints related to the average number of bonds/atom.
Abstract: This paper discusses chemical bonding effects at Si-dielectric interfaces that are important in the implementation of alternative gate dielectrics including: i) the character of interfacial bonds, either isovalent with bond and nuclear charge balanced as in Si-SiO2, or heterovalent, with an inherent mismatch between bond and nuclear charge, ii) mechanical bonding constraints related to the average number of bonds/atom, Nay, and iii) band offset energies that are reduced in transition metal oxides due to the d-state origins of the conduction band states. Applications are made to specific classes of dielectric materials including i) nitrides and oxide/nitride stacks and ii) alternative high-K gate materials.
TL;DR: In this paper, x-ray photoelectron spectroscopy experimental results on band offsets at Ge/Si(100)2 x 1 interfaces grown by hydrogen and Sb-surfactant mediated epitaxy were reported.
Abstract: We report x-ray photoelectron spectroscopy experimental results on band offsets at Ge/Si(100)2 x 1 interfaces grown by hydrogen and Sb-surfactant mediated epitaxy. For Ge deposited at 400 degrees C in Si(100)2 x 1, the valence band discontinuity was of 0.72 +/- 0.07 eV. Using atomic hydrogen and a Sb-monolayer mediated growth, we obtained values of 0.75 +/- 0.07 and 0.69 +/- 0.07 eV. Our data show that the surfactant Ge layer strain induced effects on the modification of band offsets are surprisingly negligible.
Patent•
23 Apr 1999
TL;DR: In this article, the authors make an active layer consisting of a layer whose lattice conforms to that of a GaAs substrate and which has specified components, in order to get a low-threshold current and a high slope efficiency property.
Abstract: PROBLEM TO BE SOLVED: To get a low-threshold current and a high slope efficiency property, covering a wide temperature range, by making an active layer include a layer whose lattice conforms to that of a GaAs substrate and which has specified components. SOLUTION: A buffer layer 2, a clad layer 3, a light shut-in layer 4, an active layer 5, a light shut-in layer 6, a clad layer 7, and a contact layer 8 are made in order on an n-type GaAs substrate 1. The active layer 5 is made, including an InNx ASy P1-x-y (0
TL;DR: In this paper, a gas source molecular beam epitaxy has been employed for the growth of a high quality strained-Si layer on a completely relaxed step-graded Si1−xGex buffer layer.
Abstract: Gas source molecular beam epitaxy has been employed for the growth of a high quality strained-Si layer on a completely relaxed step-graded Si1−xGex buffer layer. As-grown strained-Si layers have been characterized using secondary ion mass spectroscopy, Rutherford backscattering spectroscopy, atomic force microscopy, and spectroscopic ellipsometry for the determination of composition, thickness, crystalline quality, and surface roughness. Heterojunction conduction and valence band offsets (ΔEc, ΔEυ) of strained-Si/SiGe heterostructure have been determined from measured threshold voltages of a strained-Si channel p-metal oxide semiconductor field effect transistor (MOSFET) fabricated using grown films. MOS capacitance-voltage profiling has been employed for the extraction of strained-Si layer thickness and apparent doping profile in the device.
TL;DR: In this article, the relative valence band positions of lattice-matched alloy semiconductors are investigated with theoretical calculation, which is based on average bond energy theory in conjunction with a cluster expansion method.
Abstract: Valence band offsets at the heterointerface of lattice-matched alloy semiconductors are investigated with theoretical calculation, which is based on average bond energy theory in conjunction with a cluster expansion method. The predicted relative valence band positions of a wide range of III-V alloys are presented. The variation law of valence band offsets with composition is studied. Some trends of relative valence band positions are also presented. The theoretical results are in very good agreement with relevant experimental data. The table and figures summarizing the variation of valence band positions should be very useful in the design of novel heterostructure electronic and optical devices.
TL;DR: In this paper, the electronic structures of thin-layer superlattices (SLs) are investigated versus the SL layer thicknesses (m, n) and the band offsets, and it is shown that the existence of type-II behavior in the ultrathin-layer SLs necessitates a large valence band offset and small conduction band offset.
Abstract: The electronic structures of thin-layer superlattices (SLs) are investigated versus the SL layer thicknesses (m, n) and the band offsets. The calculations are based on the empirical tight-binding model, which includes only nearest-neighbour interactions. Particular attention is given to the effect of the interface parametrization on the SL electronic properties. This is done, mainly, by varying the band offsets over a sufficiently broad range. The results show that the existence of type-II behaviour in the ultrathin-layer SLs necessitates a large valence band offset and small conduction band offset . Providing that these offset values are achieved, it is found that the highest state of the valence band is always confined to the GaAs slabs whereas the bottom state of the conduction band shows different behaviours as it is sensitive to band-mixing effects. It is due to these mixing effects that most of the ultrathin-layer SLs (with ) behave as type-II heterostructures, where the electrons are localized in the AlAs valley. The rest of the ultrathin-layer SLs behave as type-I heterostructures with a direct bandgap at the point, whenever the GaAs slabs are thick enough to make the electron confinement energy small in the GaAs wells. For thick-layer SLs, our results suggest the existence of a critical barrier thickness, beyond which the GaAs wells become completely decoupled and the SL behaves as a type I heterostructure. The estimated critical layer thickness, for the crossover from type-I to type-II behaviour, is for the SLs with m = n when using VBO = 0.56 eV. This -value is consistent with the photoreflectance experiments. The relevance of our work to photonic device applications is discussed further.
TL;DR: In this paper, an unstrained Ga0.64In0.36As0.84Sb0.16/InP heterojunction was studied by room-temperature absorption spectroscopy.
Abstract: We report the study of unstrained Ga0.64In0.36As0.84Sb0.16/InP multiple-quantum-well structures by room-temperature absorption spectroscopy. In the absorption spectra, strong and well-resolved exciton peaks were observed. By comparing these transition energies with a theoretical calculation, we estimated the valence-band offset ratio to be 0.7±0.05 for the Ga0.64In0.36As0.84Sb0.16/InP heterojunction.
TL;DR: In this article, the effect of overlayer band bending on the interpretation of band offset measurements is discussed, and the authors show that interfacial bonding and orientation of the dipole layer are key factors in determining the direction and magnitude of the band modification.
Abstract: The ability to control semiconductor band discontinuities would allow solid devices to be specifically tailored so that efficiency and performance could be dramatically improved. This article reports the use of an ordered ZnSe monolayer to induce a valence band discontinuity at the Ge homojunction (0.38 eV), at the Ge–Si heterojunction (0.53 eV), and at the Si homojunction (∼0.2 eV). Soft x-ray photoemission was used to probe the interfaces as they were formed under ultrahigh vacuum conditions. The effect of overlayer band bending on the interpretation of band offset measurements is discussed. As the interfacial bonding and orientation of the dipole layer are key factors in determining the direction and magnitude of the band modification, x-ray standing wave measurements were performed on the Ge–ZnSe–Ge systems to identify the atomic structure of the junction. Se atoms were always found to bond to the Ge substrate in the a-top position, while the Zn atoms adopted the H3 sites, bonding to the overlayer. Th...