GaAs wafers possessing facet-dependent electrical conductivity properties

Hsieh, Pei‐Lun; Wu, Shihong; Liang, Tian; Chen, Lih‐Juann; Huang, Michael H.

doi:10.1039/d0tc00265h

Cited by 21 publications

(25 citation statements)

References 26 publications

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“…Various semiconductor materials including Cu 2 O, Ag 2 O, TiO 2 , PbS, and SrTiO 3 crystals have displayed strongly facet-dependent electrical conductivity properties. − Ag 3 PO 4 crystals, however, do not possess clear electrical facet effects . Moreover, intrinsic, or undoped, Si, Ge, and GaAs wafers also exhibit large facet dependence in their electrical conductivity responses. − In the case of Cu 2 O crystals, the {111}-bound octahedron is highly conductive, but the {110}-terminated rhombic dodecahedron is actually insulating . The {100} faces of a cube is moderately conductive.…”

Section: Introductionmentioning

confidence: 99%

Current Rectification and Photo-Responsive Current Achieved through Interfacial Facet Control of Cu₂O–Si Wafer Heterojunctions

2021

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Conductive atomic force microscopy (C-AFM) was employed to perform conductivity measurements on a facet-specific Cu2O cube, octahedron, and rhombic dodecahedron and intrinsic Si {100}, {111}, and {110} wafers. Similar I–V curves to those recorded previously using a nanomanipulator were obtained with the exception of high conductivity for the Si {110} wafer. Next, I–V curves of different Cu2O–Si heterostructures were evaluated. Among the nine possible arrangements, Cu2O octahedron/Si {100} wafer and Cu2O octahedron/Si {110} wafer combinations show good current rectification behaviors. Under white light illumination, Cu2O cube/Si {110} wafer and Cu2O rhombic dodecahedron/Si {111} wafer combinations exhibit the largest degrees of photocurrent, so such interfacial plane-controlled semiconductor heterojunctions with light sensitivity can be applied to make photodetectors. Adjusted band diagrams are presented highlighting different interfacial band bending situations to facilitate or inhibit current flow for different Cu2O–Si junctions. More importantly, the observation of clear current-rectifying effects produced at the semiconductor heterojunctions with properly selected contacting faces or planes implies that novel field-effect transistors (FETs) can be fabricated using this design strategy, which should integrate well with current chip manufacturing processes.

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Section: Introductionmentioning

confidence: 99%

Current Rectification and Photo-Responsive Current Achieved through Interfacial Facet Control of Cu₂O–Si Wafer Heterojunctions

2021

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“…Built-in potential normally refers to the potential across the depletion region of a p–n junction in thermal equilibrium. However, for the metal–intrinsic semiconductor junction here, it is assigned as the energy difference between the Schottky barrier height and the conduction band energy of the semiconductor. , The conductivity and resistivity trends do not match with the reported electrical conductivity order of different GaAs wafers, presumably because the Hall measurements are operated within −1 and 1 V in which the conductivity differences among these GaAs surfaces are small . Conductivity values of GaAs wafers are much smaller than those of Si and Ge wafers.…”

Section: Resultsmentioning

confidence: 79%

“…The Ge {111} and {211} wafers are clearly more conductive than the {110} and the lowest conductive {100} wafer . The GaAs {111} surface is notably more conductive than the {100} surface, while the {110} surface is least conductive, especially at applied voltages below 5 V …”

Section: Introductionmentioning

confidence: 99%

Large Facet-Specific Built-in Potential Differences Affecting Trap State Densities and Carrier Lifetimes of GaAs Wafers

2020

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Previously, intrinsic GaAs {111} wafers showed appreciably better electrical conductivity than the {100} wafer and the least conductive {110} wafer. Such facet dependence can be understood from subtle variation in the bond length, bond geometry, and frontier orbital electron energy distribution for different surface planes. Attempting to gain more insights about the emergence of electrical facet effects, temperature-and voltage-varying impedance measurements were performed on these GaAs wafers using silver as the contacting electrode. Parameters from the impedance and Hall effect measurements allow the presentation of the facet-specific density and energy distribution of trap states located within the GaAs band gap. Charge carrier lifetime information can also be extracted from the impedance data. Unexpectedly, the {100} surface has the largest trap state density, while the {110} surface shows the smallest density of trap states. The {111} surface also gives the longest carrier lifetime. By contrast, the most electrically conductive {111} surface in the undoped Si and Ge wafers exhibits the lowest density of trap states and shortest carrier lifetime, which are considered as characteristics of a surface with a high-conductivity property. Facet-specific GaAs−Ag band diagrams reveal both upward and downward interfacial conduction band bending cases with positive and negative built-in potentials, which resemble n-and p-type semiconductor−metal junction situations. These irregular band diagrams may partly explain the unexpected state trap density and carrier lifetime behaviors seen in the GaAs wafers, making these parameters unsuitable to relate to their electrical conductivity properties.

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“…Catalytic reactivity and selectivity are strongly influenced by the NP shape and are therefore facet dependent 4 , 5 . Shaping NPs with well defined exposed facets is an efficient strategy to enhance not only the efficiency of catalysts, but also many other physical properties such as light absorption 6 or electrical conductivity 7 . A better understanding of these facet dependent properties is therefore required to design nanomaterials with enhanced properties.…”

Section: Introductionmentioning

confidence: 99%

Imaging the facet surface strain state of supported multi-faceted Pt nanoparticles during reaction

Dupraz

Carnis

et al. 2022

Nat Commun

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Nanostructures with specific crystallographic planes display distinctive physico-chemical properties because of their unique atomic arrangements, resulting in widespread applications in catalysis, energy conversion or sensing. Understanding strain dynamics and their relationship with crystallographic facets have been largely unexplored. Here, we reveal in situ, in three-dimensions and at the nanoscale, the volume, surface and interface strain evolution of single supported platinum nanocrystals during reaction using coherent x-ray diffractive imaging. Interestingly, identical {hkl} facets show equivalent catalytic response during non-stoichiometric cycles. Periodic strain variations are rationalised in terms of O2 adsorption or desorption during O2 exposure or CO oxidation under reducing conditions, respectively. During stoichiometric CO oxidation, the strain evolution is, however, no longer facet dependent. Large strain variations are observed in localised areas, in particular in the vicinity of the substrate/particle interface, suggesting a significant influence of the substrate on the reactivity. These findings will improve the understanding of dynamic properties in catalysis and related fields.

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GaAs wafers possessing facet-dependent electrical conductivity properties

Abstract: Current-rectifying I–V curves have been recorded for {110}/{111} facet combination of a GaAs wafer, suggesting the fabrication of facet-controlled transistors.

Cited by 21 publications

References 26 publications

Current Rectification and Photo-Responsive Current Achieved through Interfacial Facet Control of Cu₂O–Si Wafer Heterojunctions

Current Rectification and Photo-Responsive Current Achieved through Interfacial Facet Control of Cu₂O–Si Wafer Heterojunctions

Large Facet-Specific Built-in Potential Differences Affecting Trap State Densities and Carrier Lifetimes of GaAs Wafers

Imaging the facet surface strain state of supported multi-faceted Pt nanoparticles during reaction

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GaAs wafers possessing facet-dependent electrical conductivity properties

Abstract: Current-rectifying I–V curves have been recorded for {110}/{111} facet combination of a GaAs wafer, suggesting the fabrication of facet-controlled transistors.

Cited by 21 publications

References 26 publications

Current Rectification and Photo-Responsive Current Achieved through Interfacial Facet Control of Cu2O–Si Wafer Heterojunctions

Current Rectification and Photo-Responsive Current Achieved through Interfacial Facet Control of Cu2O–Si Wafer Heterojunctions

Large Facet-Specific Built-in Potential Differences Affecting Trap State Densities and Carrier Lifetimes of GaAs Wafers

Imaging the facet surface strain state of supported multi-faceted Pt nanoparticles during reaction

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Current Rectification and Photo-Responsive Current Achieved through Interfacial Facet Control of Cu₂O–Si Wafer Heterojunctions

Current Rectification and Photo-Responsive Current Achieved through Interfacial Facet Control of Cu₂O–Si Wafer Heterojunctions