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Band offset

About: Band offset is a research topic. Over the lifetime, 2446 publications have been published within this topic receiving 53450 citations.


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TL;DR: In this paper, the conduction and valence band offsets of Zn1−x Sb x O/ZnO based quantum well devices were measured by photo-electron spectroscopy and consequently, the voltage-sensitive conduction band offset was calculated by UV-visible spectrographs.
Abstract: Accurate knowledge of the alignment of conduction and valence bands of layers at the heterojunction and warrant knowledge of the band offsets at the interface is essential for Zn1−x Sb x O/ZnO based quantum well device designing and modeling. Under this scenario, valence band offsets of Zn1−x Sb x O/ZnO heterostructures grown by the pulsed laser deposition technique was measured by photoelectron spectroscopy and consequently, the conduction band offset was calculated by UV-visible spectroscopy. The change in band alignment has been observed with the dopant (Sb) concentration. Ratios of conduction band offset to valence band offset were estimated to be 1.67 and 0.04 for x = 0.03 and 0.06, respectively, for Sb doped films. A Type-II band alignment was observed at the Zn0.97Sb0.03O/ZnO interface, whereas the Type-I band alignment took place at the Zn0.94Sb0.06O/ZnO interface.

14 citations

Journal ArticleDOI
TL;DR: In this article, X-ray photoelectron spectroscopy (XPS) was performed on thin layers of GaP grown on Si by metal organic chemical vapor deposition and molecular beam epitaxy.
Abstract: We have investigated the GaP/Si heterojunction interface for application in silicon heterojunction solar cells. We performed X-ray photoelectron spectroscopy (XPS) on thin layers of GaP grown on Si by metal organic chemical vapor deposition and molecular beam epitaxy. The conduction band offset was determined to be 0.9 ± 0.2 eV, which is significantly higher than predicted by Anderson's rule (0.3 eV). XPS also revealed the presence of Ga–Si bonds at the interface that are likely to be the cause of the observed interface dipole. Via cross-sectional Kelvin probe force microscopy ( x -KPFM), we observed a charge transport barrier at the Si/GaP interface which is consistent with the high-conduction band offset determined by XPS and explains the low open-circuit voltage and low fill factor observed in GaP/Si heterojunction solar cells.

14 citations

Journal ArticleDOI
TL;DR: In this article, the electrostatic effects of thin Ta2O5 layers on the band alignments of MOS devices are examined, and the possible use for these effects in devices is discussed.
Abstract: Thin dielectric layers are a prominent route to control the band alignments and effective work function of metal oxide semiconductor (MOS) devices. In this work, the electrostatic effects of thin Ta2O5 layers on the band alignments of MOS devices are examined. A detailed analysis of the physical properties of a thick (∼6 nm) Ta2O5 layer is reported. No significant dipoles at Ta2O5-Al2O3 and Ta2O5-SiO2 interfaces are found, as well as any significant charges inside Ta2O5 layers. When positioned at the interface, Ta2O5 is shown to prevent the formation of band offsets between Al2O3-SiO2, resulting in a shift of 1 ± 0.2 eV versus samples without interfacial Ta2O5. The relatively large magnitude of this shift in the current experimental configuration compared to previous works may indicate the participation of interface charges in the band offset. The possible use for these effects in devices is discussed.

14 citations

Journal ArticleDOI
TL;DR: Measurements of the Al 2p to Ga 3d core level energy separations indicate that the band offset for GaAs/AlAs (100) is commutative; the value the authors obtain is DeltaEv=0.46±0.07 eV.
Abstract: X-ray photoelectron spectroscopy is used to measure the valence-band offset in situ for GaAs/AlAs (100) heterojunctions grown by molecular beam epitaxy. Ga 3d and Al 2p core level to valence-band edge binding energy differences are measured in GaAs (100) and AlAs (100) samples, respectively, and the Al 2p to Ga 3d core level binding energy difference is measured in GaAs–AlAs (100) and AlAs–GaAs (100) heterojunctions. Measurements of the Al 2p to Ga 3d core level energy separations indicate that the band offset for GaAs/AlAs (100) is commutative; the value we obtain is DeltaEv=0.46±0.07 eV. Our observation of commutativity is believed to be a consequence of the high quality of our GaAs/AlAs (100) heterojunctions, and of the inherent commutativity of the GaAs/AlAs (100) band offset.

14 citations

Journal ArticleDOI
TL;DR: In this paper, the optical properties of lattice-matched InP/AlxGa1?xAsSb layers for 0? x? 0.17 have been investigated by photoluminescence (PL) spectroscopy at 15 K.
Abstract: The optical properties of lattice-matched InP/AlxGa1?xAsSb layers for 0 ? x ? 0.17 have been investigated by photoluminescence (PL) spectroscopy at 15 K. The PL revealed emission peaks corresponding to the band-to-band transitions of AlGaAsSb and InP. Moreover, a second emission due to the spatially indirect recombination (type-II) of electrons in the conduction band (CB) of InP and holes in the valence band (VB) of AlGaAsSb was also observed. The CB and VB offsets between InP and AlGaAsSb are determined for different Al concentrations directly from the measured transitions. Furthermore, the strong type-II PL shift induced by varying the excitation intensity is compared to theoretical predictions.

14 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202336
202267
202178
202085
201980
201882