Electron transport through planar defects: a new description of grain boundary scattering

Knäbchen, Andreas

doi:10.1088/0953-8984/3/36/004

Cited by 11 publications

(8 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Both calculations, however, overestimate the reflectance of the 15 film, see Fig 6. It is seen that the discrepancy we observe between computed and experimental reflectance increases as the grain size decreases, because, as suggested in Ref. 12, the assumption of additivity of inverse relaxation times becomes less accurate. This may also be due to our assumption of a columnar geometry for the grains of the film.…”

Section: A Visible and Near Infraredmentioning

confidence: 53%

“…Electron transport properties of metal films taking account of grain boundaries have been studied over the years by several authors, using a variety of methods including the Boltzmann transport equation ͑and related approaches͒, [1][2][3][4][5][6][7] the transfer matrix in a onedimensional ͑1D͒ quantum mechanical setting, 8 the energy loss concept, [9][10][11] and the superposition method. 12 Knowledge of the effect of grain boundaries in the electronic transport in these films may be used to obtain information on the microgeometry of the film, 10 analyze the transport properties of nonequilibrium electrons 13 and surface plasmons, 14 to name just a few applications.…”

Section: Introductionmentioning

confidence: 99%

“…Admittedly, this assumption may be doubted because it is just another way to write Mathiessen's rule which is known to be violated in such a case. 15 Still, the assumption has been proven to hold, for instance, when the mean film grain size D is larger than the mean free path of the homogeneous background ϱ , 12 and has even been pushed a little further to deal with some cases where DՇ ϱ . 12 Thus, the boundary of its applicability is not clearly defined.…”

Section: Introductionmentioning

confidence: 99%

“…15 Still, the assumption has been proven to hold, for instance, when the mean film grain size D is larger than the mean free path of the homogeneous background ϱ , 12 and has even been pushed a little further to deal with some cases where DՇ ϱ . 12 Thus, the boundary of its applicability is not clearly defined. In spite of the model's shortcomings, its simplicity makes it appealing and useful as a first approximation when interpreting experimental data on electronic transport.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Optical properties of polycrystalline metallic films

2003

View full text Add to dashboard Cite

show abstract

Section: A Visible and Near Infraredmentioning

confidence: 53%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Optical properties of polycrystalline metallic films

2003

View full text Add to dashboard Cite

show abstract

“…The reflection coefficient, R g , can be estimated from a knowledge of the mean free path, the voltage drop at the boundary and the electric field component perpendicular to the grain [11,18]. We estimated the values of R g at different points for several grains.…”

Section: Resultsmentioning

confidence: 99%

A study of the spatial variation of electric field in highly resistive metal films by scanning tunneling potentiometry

Ramaswamy¹,

Raychaudhuri²,

Gupta³

et al. 1998

Applied Physics A: Materials Science & Processing

View full text Add to dashboard Cite

Electronic transport in highly resistive (but metallic) thin platinum films (≈ 10 nm) deposited by electronbeam evaporation has been studied by scanning tunneling microscopy and scanning tunneling potentiometry (STP). The films have an average grain size of ≈ 10 nm. On this scale transport through the film is very inhomogeneous. Scattering from grain boundaries (GBs) results in large variations in the local potential resulting in fields as high as 10 4 -10 5 V/cm located near the GB. The reflection coefficient R g of electrons at a GB has values between 0.5-0.7 as determined from the STP data. This can be compared to an average R g ≈ 0.9 obtained from an analysis of the bulk resistivity data taken over the temperature range 4.2 K < T < 300 K.Charge transport in thin metal films is not uniform on the nanometer scale and is accompanied by strong inhomogeneities in the field and current density near localized scatterers such as grain boundaries (GBs) and defects. Conventional theories of transport ignore these spatial variations and consider the averaged field. In this average picture all details of the charge transport in the conductor are parameterized by a single parameter, namely the mean free path of the charge carrier. This describes the correct picture in a bulk system but as the sample dimension decreases it becomes necessary to measure the relevant quantities on a nanometer scale and the deviations of the local fields and potentials from the average values become significant. The significance of the influence of localized scatterers was first recognized and investigated theoretically by Landauer [1]. He pointed out that the microscopic dipole field that results from the asymmetry of the electron scattering at a point defect is the ultimate source of the residual resistivity. Work of Landauer and subsequent developments [2,3] showed the equivalence of the residual resistivity dipole approach and the more conventional Boltzmann transport approach. Understanding the exact microscopic nature of the scattering process is important in order to gain insight into fundamental questions like charge transport at the nanometer scale and is also of practical interest in phenomena like electromigration. While bulk transport properties which give a measure of the average behavior have been investigated for a long time, the actual electronic processes taking place at a nanometer level (at the scale of electronic mean free path) remained essentially unanswered mainly because of the lack of an experimental tool to study the properties on this scale. Development of scanning probe microscopies (SPMs) [4,5] and in particular scanning tunneling potentiometry (STP) [6-8] has enabled us to experimentally observe the scattering-induced field variations at a nanometer scale. More recent theoretical studies have established the condition under which scanning tunneling microscopy (STM) can measure the change in local electrochemical potential [9]. It is only recently with the advent of STP that this issue is being reinvestigated and a...

show abstract

Scanning tunneling potentiometry study of electron reflectivity of a single grain boundary in thin gold films

Schneider

Wenderoth

Heinrich

et al. 1997

J. Electron. Mater.

View full text Add to dashboard Cite

Spatial variations of the local electric field in current-carrying thin gold films were studied with a scanning tunneling microscope on a nanometer scale. With a refined scanning tunneling potentiometry technique, it was possible to determine the local electric fields within single grains. At grain boundaries, we observe potential drops on length scales of less than 1 nm which exceed the potential difference within a grain greatly. We interpret our findings by applying a theory that models grain boundaries as barriers with a reflectivity R for the conduction electrons. With the assumption of isotropic background scattering within each grain, we determine the local current-density j(x,y) that passes a grain boundary. From that, we obtain the reflectivity of individual grain boundaries and find values of R = 0.7 to R = 0.9 which is much higher than expected from macroscopic experiments.

show abstract

Electron transport through planar defects: a new description of grain boundary scattering

Cited by 11 publications

References 19 publications

Optical properties of polycrystalline metallic films

Optical properties of polycrystalline metallic films

A study of the spatial variation of electric field in highly resistive metal films by scanning tunneling potentiometry

Scanning tunneling potentiometry study of electron reflectivity of a single grain boundary in thin gold films

Contact Info

Product

Resources

About