Band offsets measured by internal photoemission-induced second-harmonic generation

Márka, Z.; Pasternak, R.; Rashkeev, Sergey N.; Jiang, Yongqiang; Pantelides, Sokrates T.; Tolk, N. H.; Roy, P.K.; Kozub, John A.

doi:10.1103/physrevb.67.045302

Cited by 29 publications

(27 citation statements)

References 25 publications

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“…5,7,8 In addition, the SiO 2 / c-Si system was the first system where time-dependent variations in the SHG intensity due to photon-induced charge trapping, which resulted in changes in the EFISH contribution, were observed. [10][11][12][13] The characterization of ͑hydrogenated͒ amorphous Si films by SHG as used in this study is relatively unexplored. Erley and Daum 5 reported on ex situ SHG experiments of a 0.7 m thick a-Si: D film on Si͑100͒ and observed a very weak featureless SHG spectrum that was an order of magnitude lower in intensity than for native oxide covered Si͑100͒.…”

Section: Introductionmentioning

confidence: 99%

Optical second-harmonic generation in thin film systems

Gielis

Gevers

Aarts

et al. 2008

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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Document VersionPublisher's PDF, also known as Version of Record (includes final page, issue and volume numbers) Please check the document version of this publication:• A submitted manuscript is the author's version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website.• The final author version and the galley proof are versions of the publication after peer review.• The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. The surface and interface sensitive nonlinear optical technique of second-harmonic generation ͑SHG͒ is a very useful diagnostic in studying surface and interface properties in thin film systems and can provide relevant information during thin film processing. An important aspect when applying SHG is the interpretation of the SHG response. In order to utilize the full potential of SHG during materials processing it is necessary to have a good understanding of both the macroscopic and the microscopic origin of the SHG response, particularly in thin film or multilayer systems where the propagation of radiation is another important aspect that should be considered carefully. A brief theoretical overview on the origin of the SHG response and a description of the propagation of radiation will be given. Furthermore, several methods will be discussed that might reveal the possible macroscopic and microscopic origins of the SHG response in thin film systems. The different approaches will be illustrated by examples of real-time and spectroscopic SHG experiments with thin film systems relevant in Si etching and deposition environments, such as ͑1͒ hydrogenated amorphous Si films deposited by hot-wire chemical vapor deposition on both Si͑100͒ and fused silica substrates, ͑2͒ amorphous Si generated by low-energy Ar + -ion bombardment of H terminated Si͑100͒, and ͑3͒ Al 2 O 3 films deposited by plasma-assisted atomic layer deposition on H terminated Si͑100͒.

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Section: Introductionmentioning

confidence: 99%

Optical second-harmonic generation in thin film systems

Gielis

Gevers

Aarts

et al. 2008

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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“…2, this leads to a discontinuous change in materials parameters at x = w/2. We take N c,v ,μ, D, and the permittivity ǫ to be constant outside the space-charge region x L < x < x R , and hence label them by indices L and R. The width of a spacecharge region is x R −x L ∝ (V bi −V ) 1/2 , where the built-in voltage is qV bi = −∆E c + k B T ln(n 0R N cR /n 0L N cL ); we note that the discontinuity ∆E c,v can be accurately measured at interfaces with Si [21]. Equations (2) and (3), together with the continuity equations, reduce to diffusionlike equations for δn, δs in the p-region and δp, δs in the n-region.…”

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confidence: 99%

Spin Injection and Detection in Silicon

2006

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Spin injection and detection in silicon is a difficult problem, in part because the weak spin-orbit coupling and indirect gap preclude using standard optical techniques. We propose two ways to overcome this difficulty, and illustrate their operation by developing a model for spin-polarized transport across a heterojunction. We find that equilibrium spin polarization of holes leads to a strong modification of the spin and charge dynamics of electrons, and we show how the symmetry properties of the charge current can be exploited to detect spin injection in silicon using currently available techniques.In addition to its central role in conventional electronics, silicon has spin-dependent properties (such as long spin relaxation and decoherence times) that could be particularly useful in spin-based quantum-information processing and spintronics [1]. Unfortunately, the underlying origins of these attractive properties-the indirect band gap, weak spin-orbit coupling, and extremely small concentration of paramagnetic impurities [2]-also preclude using the standard optical methods of spin injection and detection in semiconductors.Circularly polarized light can be used to polarize carriers in semiconductors with a direct band gap. Moreover, both the direction and the magnitude of optically generated charge currents [3,4] and pure spin currents [5,6] can be controlled optically. In the reverse process, the presence of polarized carriers in a direct-gap semiconductor can be detected by measuring the circular

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“…The pumping rates, and thus the electric field and EFISH signal, vary with the order of the multiphoton process, which depends on the photon energy. Tuning the pump beam then allows thresholds for the internal photoemission process to be identified and band offsets measured [91].…”

Section: Temporal Studiesmentioning

confidence: 99%

Probing surface and interface structure using optics

McGilp

2010

J. Phys.: Condens. Matter

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Optical techniques for probing surface and interface structure are introduced and recent developments in the field are discussed. These techniques offer significant advantages over conventional surface probes: all pressure ranges of gas-condensed matter interfaces are accessible and liquid-liquid, liquid-solid and solid-solid interfaces can be probed, due to the large penetration depth of the optical radiation. Sensitivity and discrimination from the bulk are the two challenges facing optical techniques in probing surface and interface structure. Where instrumental improvements have resulted in enhanced sensitivity, conventional optical techniques can be used to characterize heterogeneous adsorbed layers on a substrate, often with sub-monolayer resolution. Nanoscale lateral resolution is possible using scanning near-field optics. A separate class of techniques, which includes reflection anisotropy spectroscopy, and nonlinear optical probes such as second-harmonic and sum-frequency generation, uses the difference in symmetry between the bulk and the surface or interface to suppress the bulk contribution. A perspective is presented of likely future developments in this rapidly expanding field.

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Band offsets measured by internal photoemission-induced second-harmonic generation

Cited by 29 publications

References 25 publications

Optical second-harmonic generation in thin film systems

Optical second-harmonic generation in thin film systems

Spin Injection and Detection in Silicon

Probing surface and interface structure using optics

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