Microscopic study of semiconductor heterojunctions: Photoemission measurement of the valance-band discontinuity and of the potential barriers

Katnani, A. D.; Margaritondo, G.

doi:10.1103/physrevb.28.1944

Cited by 319 publications

(71 citation statements)

References 44 publications

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“…Such vapor phase studies should provide a reasonable, qualitative approximation of the chemical species present when the solid is in contact with a bulk-like electrolyte. The connection between the gas phase AP-XPS studies and AP-HAXPES studies at semiconductor/bulk-like aqueous electrolyte interfaces can be strengthened by building the electrolyte film in a step-wise manner (see Figure 1), a method analogous to what has long been used in UHV conditions to understand solid/solid interfaces [39,40].…”

Section: Ap-xps and Ap-haxpesmentioning

confidence: 99%

“…Such an approach has been recently used to study band alignment at the solid-solid interface formed between silicon and TiO 2 protection layers for photoelectrochemical applications [21]. A standard experimental procedure for conducting these studies is to vacuum deposit a solid overlayer, layer-by-layer onto the substrate while simultaneously monitoring both valence and core-level spectra [22]. In this way the valence states and core level binding energy shifts can be monitored as the interface is formed to determine band alignment between the substrate and overlayer.…”

Section: Correlating Interfacial Chemistry and Band Edge Positionsmentioning

confidence: 99%

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Combined soft and hard X-ray ambient pressure photoelectron spectroscopy studies of semiconductor/electrolyte interfaces

Starr

Favaro

Abdi

et al. 2017

Journal of Electron Spectroscopy and Related Phenomena

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The development of solar fuel generating materials would greatly benefit from a molecular level understanding of the semiconductor/electrolyte interface and changes in the interface induced by an applied potential and illumination by solar light. Ambient pressure photoelectron spectroscopy techniques with both soft and hard X-rays, AP-XPS and AP-HAXPES respectively, have the potential to markedly contribute to this understanding. In this paper we initially provide two examples of current challenges in solar fuels material development that AP-XPS and AP-HAXPES can directly address. This will be followed by a brief description of the distinguishing and complementary characteristics of soft and hard X-ray AP-XPS and AP-HAXPES and best approaches to achieving monolayer sensitivity in solid/aqueous electrolyte studies. In particular we focus on the detection of adsorbed hydroxyl groups in the presence of aqueous hydroxyls in the electrolyte, a common situation when investigating photoanodes for solar fuel generating applications. The paper concludes by providing an example of a combined AP-XPS and AP-HAXPES study of a semiconductor/aqueous electrolyte interface currently used in water splitting devices specifically the BiVO 4 /aqueous potassium phosphate electrolyte interface.2

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Section: Ap-xps and Ap-haxpesmentioning

confidence: 99%

Section: Correlating Interfacial Chemistry and Band Edge Positionsmentioning

confidence: 99%

Combined soft and hard X-ray ambient pressure photoelectron spectroscopy studies of semiconductor/electrolyte interfaces

Starr

Favaro

Abdi

et al. 2017

Journal of Electron Spectroscopy and Related Phenomena

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show abstract

“…(2)- (5) m is the hole effective mass, ε and ε0 are the semiconductor and vacuum permittivities (for InP m p /m 0 = 0.64 and ε = 12.61 [7]), Vb and V, are the separations between EF and Εv at the interface and in the bulk of InP, respectively, and Nd is the acceptor concentration (Nd = 1.6 x 10 19 cm-3 ). Using the relations given above and assuming Vb = 0.8 eV [8], we calculated the dependences of Vh vs. jph (dashed curves in Fig. 2).…”

Section: Si/p-~ιnp(110) Heterojunctionmentioning

confidence: 99%

Surface Photovoltage in Photoemission Studies at Si/InP(110) Heterojunctions

1995

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We discuss the surface photovoltage effect observed in photoemission experiment performed at room (300 K) and low (120 K) temperatures on Si/InP(110) heterojunctions for a thin Si coverage on n-and p-doped InP substrates. The theoretical analysis of the surface photovoltage effect has been performed on the basis of thermionic and thermionic-field emission models of transport processes in Schottky barriers.

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“…(A literature review of heterojunction band alignment at the Si/GaAs interface suggests E v spanning 0.03 eV and 0.38 eV. [26][27][28][29][30][31][32][33][34][35] This spread in band alignment values is thought to exist because the electron affinity rule is an ideal case but interface states, dipole interactions, strain, and surface reconstructions present non-idealities which modify band alignment from this ideal. 36 ) In this work, band alignments are modeled in 1D using nextnano, a Poisson solver, using the electron affinity rule as a basis.…”

mentioning

confidence: 99%

Silicon CMOS Ohmic Contact Technology for Contacting III-V Compound Materials

Pacella

Mukherjee

Bulsara

et al. 2013

ECS J. Solid State Sci. Technol.

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Silicon (Si)-encapsulated III-V compound (III-V) device layers enable Si-complementary metal-oxide semiconductor (CMOS) friendly ohmic contact formation to III-V compound devices, allowing for the ultimate seamless planar integration of III-V and Si CMOS devices in a common fabrication infrastructure. A method of making ohmic contacts to buried III-V films using silicide metallurgies has been established. NiSi/Si/III-V dual heterojunction contact structures are found to be optimal for integration. These structures allow contact resistivities to be controlled by Si/III-V interfaces and eliminate interactions between the buried III-V device and metal layers. Using a modified transmission line method (TLM) test structure fabricated using standard CMOS processing techniques, the specific contact resistivities of Si/GaAs and Si/In x Ga 1-x As interfaces are extracted. The relationship between specific contact resistivity and heterojuntion barrier width is considered. Among the structures tested in this work, p-type Si/GaAs and n-type Si/In x Ga 1-x As yielded the lowest contact resistivities. Using the p-type Si/GaAs interface, a GaAs/Al x Ga 1-x As laser with NiSi top contact is demonstrated, confirming the feasibility of NiSi/Si/III-V contact structures for III-V devices. Integration of III-V compound (III-V) semiconductors with Si complementary metal-oxide semiconductor (CMOS) has been an area of great interest because of the circuit performance enhancement that can be gained by placing Si and III-V devices in close spatial proximity. The Silicon-on-Lattice-Engineered Substrate (SOLES) platform enables this integration monolithically. The SOLES wafer is a silicon wafer with an embedded template suitable for epitaxial III-V device growth.1-3 CMOS devices are fabricated on the surface silicon and III-V devices are built on the template layer in windows. In collaboration with other groups, we have successfully demonstrated differential amplifiers with InP heterojunction bipolar transistors (HBT) and Si CMOS devices on SOLES substrates. 4 In this previous work, Si and III-V contact metallization steps were performed separately in traditional CMOS and III-V infrastructure, respectively. We envision parallel metallization of the CMOS and III-V devices using common CMOS infrastructure, in a manner consistent with Si processing, as a final step toward ultimate monolithic integration.A few key requirements must be considered in choosing the optimal contact structure. Contacting the III-V films through a Si encapsulation layer which fully embeds the III-V device and minimizes exposure of III-V materials to the CMOS sequence will cause the least disruption to CMOS processes. This Si may be grown in an epitaxial step that is integrated with III-V device growth, streamlining the growth process.Using CMOS-friendly metals and processing steps which parallel those currently found in CMOS processing will also ease the integration. This metal must have a thermal budget of formation that is low to minimize effects on the III-V devic...

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Microscopic study of semiconductor heterojunctions: Photoemission measurement of the valance-band discontinuity and of the potential barriers

Cited by 319 publications

References 44 publications

Combined soft and hard X-ray ambient pressure photoelectron spectroscopy studies of semiconductor/electrolyte interfaces

Combined soft and hard X-ray ambient pressure photoelectron spectroscopy studies of semiconductor/electrolyte interfaces

Surface Photovoltage in Photoemission Studies at Si/InP(110) Heterojunctions

Silicon CMOS Ohmic Contact Technology for Contacting III-V Compound Materials

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