Interface-induced gap states and band-structure lineup at TiO2 heterostructures and Schottky contacts

2010 ◽  
Vol 107 (1) ◽  
pp. 013706 ◽  
Author(s):  
Winfried Mönch
Keyword(s):  
Band Structure ◽  
Schottky Contacts ◽  
Gap States

Metal Contacts on a-GaN

1996 ◽  
Vol 1 ◽  
Author(s):  
T. U. Kampen ◽  
W. Mönch
Keyword(s):  
Tight Binding ◽  
Image Force ◽  
Schottky Contacts ◽  
Metal Contacts ◽  
Zero Bias ◽  
Barrier Heights ◽  
Current Voltage ◽  
Optical Dielectric Constant ◽  
Optical Dielectric ◽  
Gap States

The Schottky barrier heights of silver and lead contacts on n-type GaN (0001) epilayers were determined from current-voltage characteristics. The zero-bias barrier heights and the ideality factors were found to be linearly correlated. Similar observations were previously reported for metal contacts on Si (111) and GaAs (110) surfaces. The barrier heights of ideal Schottky contacts are characterized by image force lowering of the barrier only. This gives an ideality factor of 1.01. From our data we obtain barrier heights of 0.82 eV and 0.73eV for ideal Ag and Pb contacts on GaN, respectively. The metal-induced gap states (MIGS) model predicts the barrier heights of ideal Schottky contacts on a given semiconductor to be linearly correlated with the electronegativities of the metals. The two important parameters of this MIGS-and-electronegativity model are the charge neutrality level (CNL) of the MIGS and a slope parameter. The CNL may be calculated from the dielectric band gap and using the empirical tight-binding method. The slope parameters are given by the optical dielectric constant of the respective semiconductor. The predictions of the MIGS model for metal/GaN contacts are confirmed by the results presented here and by barrier heights previously reported by others for Au, Ti, Pt, and Pd contacts on GaN.

Band Structure Calculations and Magnetic Relaxation in Correlated Semiconductors FeSb2 and RuSb2

2009 ◽  
Vol 152-153 ◽  
pp. 287-290 ◽  
Author(s):  
A.A. Gippius ◽  
K.S. Okhotnikov ◽  
M. Baenitz ◽  
A.V. Shevelkov
Keyword(s):  
Band Structure ◽  
Magnetic Relaxation ◽  
Narrow Band ◽  
Relaxation Mechanism ◽  
Activation Mechanism ◽  
Oxidation Number ◽  
Band Structure Calculations ◽  
Gap States ◽  
Structure Calculations ◽  
Behavior Characteristic

A comparative study of electronic properties of the two isostructural narrow-band semiconductors FeSb2 and RuSb2 by means of experimental NQR spectroscopy as well as theoretical ab-initio band structure calculations is presented. The temperature dependence of 1/T1 consists of two distinct intervals: above 40 K (HT) with activated behavior for FeSb2 with D/kB @ 450 K and below 40 K (LT) with smooth maximum at 10 K. Here the relaxation is governed by in-gap states. We propose the model of inherent Sb-deficiency (as prepared non-stoichiometry) of both FeSb2 and RuSb2 as a possible reason of the in-gap states. This results in creation of a small portion of Fe (Ru) ions possessing formal oxidation number +3 with d5 configuration and forming narrow energy level of localized S = ½ spins near the bottom of the conduction band. Due to much higher gap value in RuSb2, the activation mechanism for RuSb2 in the HT range is inefficient and the 1/T1 dependence in the HT range is more close to T2 behavior characteristic for phonon relaxation mechanism by two-phonon (Raman) scattering.

Intrinsic Gap States in Semiconductors with Inverted Band Structure: Comparison of SnTe vs PbTe Nanocrystals

2019 ◽  
Vol 123 (18) ◽  
pp. 11974-11981
Author(s):  
Roman Vaxenburg ◽  
Janice E. Boercker ◽  
Danielle L. Woodall ◽  
Chase T. Ellis ◽  
C. Stephen Hellberg ◽  
...  
Keyword(s):  
Band Structure ◽  
Structure Comparison ◽  
Gap States
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