Atomistic approach for modeling metal-semiconductor interfaces

Author(s):  
Daniele Stradi ◽  
Umberto Martinez ◽  
Anders Blom ◽  
Mads Brandbyge ◽  
Kurt Stokbro
Author(s):  
Z. Liliental-Weber ◽  
C. Nelson ◽  
R. Ludeke ◽  
R. Gronsky ◽  
J. Washburn

The properties of metal/semiconductor interfaces have received considerable attention over the past few years, and the Al/GaAs system is of special interest because of its potential use in high-speed logic integrated optics, and microwave applications. For such materials a detailed knowledge of the geometric and electronic structure of the interface is fundamental to an understanding of the electrical properties of the contact. It is well known that the properties of Schottky contacts are established within a few atomic layers of the deposited metal. Therefore surface contamination can play a significant role. A method for fabricating contamination-free interfaces is absolutely necessary for reproducible properties, and molecularbeam epitaxy (MBE) offers such advantages for in-situ metal deposition under UHV conditions


Author(s):  
S. J. Pennycook

Using a high-angle annular detector on a high-resolution STEM it is possible to form incoherent images of a crystal lattice characterized by strong atomic number or Z contrast. Figure 1 shows an epitaxial Ge film on Si(100) grown by oxidation of Ge-implanted Si. The image was obtained using a VG Microscopes' HB501 STEM equipped with an ultrahigh resolution polepiece (Cs ∽1.2 mm, demonstrated probe FWHM intensity ∽0.22 nm). In both crystals the lattice is resolved but that of Ge shows much brighter allowing the interface to be located exactly and interface steps to be resolved (arrowed). The interface was indistinguishable in the phase-contrast STEM image from the same region, and even at higher resolution the location of the interface is complex. Figure 2 shows a thin region of an MBE-grown ultrathin super-lattice (Si8Ge2)100. The expected compositional modulation would show as one bright row of dots from the 2 Ge monolayers separated by 4 rows of lighter Si columns. The image shows clearly that strain-induced interdiffusion has occurred on the monolayer scale.


2021 ◽  
Vol 118 (2) ◽  
pp. 021104
Author(s):  
Kil-Song Song ◽  
Song-Jin Im ◽  
Ji-Song Pae ◽  
Chol-Song Ri ◽  
Kum-Song Ho ◽  
...  

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1581
Author(s):  
José C. Conesa

Two DFT-based methods using hybrid functionals and plane-averaged profiles of the Hartree potential (individual slabs versus vacuum and alternating slabs of both materials), which are frequently used to predict or estimate the offset between bands at interfaces between two semiconductors, are analyzed in the present work. These methods are compared using several very different semiconductor pairs, and the conclusions about the advantages of each method are discussed. Overall, the alternating slabs method is recommended in those cases where epitaxial mismatch does not represent a significant problem.


2021 ◽  
pp. 108041
Author(s):  
Lis K. Nanver ◽  
Lin Qi ◽  
Xingyu Liu ◽  
Tihomir Knežević

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1188
Author(s):  
Ivan Rodrigo Kaufmann ◽  
Onur Zerey ◽  
Thorsten Meyers ◽  
Julia Reker ◽  
Fábio Vidor ◽  
...  

Zinc oxide nanoparticles (ZnO NP) used for the channel region in inverted coplanar setup in Thin Film Transistors (TFT) were the focus of this study. The regions between the source electrode and the ZnO NP and the drain electrode were under investigation as they produce a Schottky barrier in metal-semiconductor interfaces. A more general Thermionic emission theory must be evaluated: one that considers both metal/semiconductor interfaces (MSM structures). Aluminum, gold, and nickel were used as metallization layers for source and drain electrodes. An organic-inorganic nanocomposite was used as a gate dielectric. The TFTs transfer and output characteristics curves were extracted, and a numerical computational program was used for fitting the data; hence information about Schottky Barrier Height (SBH) and ideality factors for each TFT could be estimated. The nickel metallization appears with the lowest SBH among the metals investigated. For this metal and for higher drain-to-source voltages, the SBH tended to converge to some value around 0.3 eV. The developed fitting method showed good fitting accuracy even when the metallization produced different SBH in each metal-semiconductor interface, as was the case for gold metallization. The Schottky effect is also present and was studied when the drain-to-source voltages and/or the gate voltage were increased.


2021 ◽  
Vol 3 (3) ◽  
pp. 1384-1393
Author(s):  
Natalie P. Holmes ◽  
Daniel C. Elkington ◽  
Matthew Bergin ◽  
Matthew J. Griffith ◽  
Anirudh Sharma ◽  
...  

2012 ◽  
Vol 100 (17) ◽  
pp. 171915 ◽  
Author(s):  
H. Wolf ◽  
J. Kronenberg ◽  
F. Wagner ◽  
M. Deicher ◽  
Th. Wichert ◽  
...  

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