The Density of States in a-Si:C:H Revealed by Electrophotography

1993 ◽  
Vol 297 ◽  
Author(s):  
R.A.C.M.M. Van Swaaij ◽  
W.P.M. Willems ◽  
J. Bezemer ◽  
M.B. Von Der Linden ◽  
W.F. Van Der Weg
Keyword(s):  
Conduction Band ◽  
Density Of States ◽  
Carbon Concentration ◽  
Band Edge ◽  
Conduction Band Edge ◽  
Temperature Dependent ◽  
Energy Position ◽  
A Value ◽  
Dark Decay ◽  
Bulk Space

Electrophotographic dark decay measurements have been used to determine the surface density of states (SDOS) of a-Si:C:H. Injection of trapped charge from these deep states into the conduction band governs the dark discharge of a photoconductor, provided bulk generation and bulk space charge are negligible. It is found that the SDOS profiles peak around 0.60 eV below the conduction band for materials with different carbon concentration. This observation implies that the energy position of these states is fixed with respect to the conduction band edge, even though the optical band gap of these materials increases with increasing carbon concentration. The nature of these states may be ascribed to D− states, whose density is strongly enhanced by filling D° states when the material is charged negatively. Furthermore, we observed that the SDOS around 0.60 eV below the conduction band edge is approximately the same for materials with up to 8 at.% carbon. From temperature dependent measurements a value of 2·108 s−1 was obtained for the attempt-to-escape frequency.

Characterization of Localized Density of States in Intrinsic a-Si and poly-Si Films by Transient Voltage Spectroscopy

1995 ◽  
Vol 377 ◽  
Author(s):  
G. Kawachi ◽  
M. Ishii ◽  
T. Tanaka ◽  
N. Konishi
Keyword(s):  
Conduction Band ◽  
Density Of States ◽  
Band Edge ◽  
Conduction Band Edge ◽  
High Impedance ◽  
Pool Model ◽  
Transient Voltage ◽  
Mis Diode ◽  
Si Films

ABSTRACTThe localized density of states (LDOS) at interfaces between intrinsic silicon and silicon nitride (Si3N4 films are studied using transient voltage spectroscopy (TVS). In the TVS technique, the transient of the voltage across a MIS-diode after a trap filling voltage pulse is measured using a high-impedance voltage probe. This allows us to make a precise measurement of the LDOS at undoped Si/insulator interfaces. The LDOS in a-Si:H/Si3N4systems has a broad peak around the energy of 0.9 eV below the conduction-band edge. A modification of the LDOS at a-Si:H/Si3N4 interfaces by bias-annealing is clearly observed using this technique. The results are consistent with the defect pool model. The LDOS in laser annealed poly-Si/Si3N4 systems has a peak centered 0.6eV below the conduction-band edge, which seems to be the Si dangling bond states in the poly-Si films.

Temperature-dependent Hall and photoluminescence evidence for conduction-band edge shift induced by alloying ZnO with magnesium

2009 ◽  
Vol 95 (15) ◽  
pp. 152105 ◽  
Author(s):  
X. H. Pan ◽  
W. Guo ◽  
Z. Z. Ye ◽  
B. Liu ◽  
Y. Che ◽  
...  
Keyword(s):  
Conduction Band ◽  
Band Edge ◽  
Conduction Band Edge ◽  
Temperature Dependent

First principles study of electronic structures of dopants in Mg2Si

2011 ◽  
Vol 1329 ◽  
Author(s):  
K. Xiong ◽  
S. Sobhani ◽  
R. P. Gupta ◽  
W. Wang ◽  
B. E. Gnade ◽  
...  
Keyword(s):  
Band Gap ◽  
Valence Band ◽  
Conduction Band ◽  
Density Of States ◽  
First Principles ◽  
Band Edge ◽  
Conduction Band Edge ◽  
Hybrid Functional ◽  
Thermoelectric Efficiency ◽  
The Impact

ABSTRACTWe investigate the impact of various dopants (Na, Ag, Cd, Zn, Al, Ga, In, Tl, Ge, and Sn) on the electronic structure of Mg2Si by first principles calculations using a hybrid functional that does not need a band gap correction. We find that for Na and Ge in Mg2Si, the impurity-induced states do not affect the density of states at both edges of the valence band and the conduction band. Ag- and Sn affect slightly the density of states at the valence band edge, while Cd and Zn affect slightly the density of state at the conduction band edge. Al and In could modify significantly the density of states at the conduction band edge. Ga introduces states just at the bottom of the conduction band. Tl introduces states in the band gap. This study provides useful information on optimizing the thermoelectric efficiency of Mg2Si.

Investigation of Interface States on Mbe CoSi2/Si Schottky Contacts by Forward Bias Capacitance Measurement

1987 ◽  
Vol 91 ◽  
Author(s):  
H. Y. Chen ◽  
Y. C. Kao ◽  
Y. J. Mii ◽  
K. L. Wang
Keyword(s):  
Conduction Band ◽  
Density Of States ◽  
Forward Bias ◽  
Interface State ◽  
Interface States ◽  
Band Edge ◽  
Conduction Band Edge ◽  
Capacitance Measurement ◽  
Electron Capture Cross Section ◽  
State Band

ABSTRACTThe properties of the interface states of MBE grown CoSi2/n-Si(111) intimate contacts has been investigated using forward bias capacitance measurement. The barrier height øbn for this structure is 0.66±0.01 V. It has been found that there is an interface state band located in 0.44–0.50 eV bfow the conduction band edge of Si. The density of states D it is about 4×1012 cm−2 eV−1, lower than those made by other methods. This intrface state band is in equilibrium with Si and the charge exchange occurs mainly with the electrons in the conduction band of Si. The electron capture cross section oa is about 3×10−15 cm2 . In addition, some discrete interface states were found at 0.53 eV, 0.51 eV and 0.47 eV below the conduction band edge of Si, respectively for several samples. The density of states D it ranges (1.5–3.5)×1010 cm−2 . They are probably caused by localized point defects formed during CoSi2 growth.

scholarly journals Conduction Band Edge Energy Profile Probed by Hall Offset Voltage in InGaZnO Thin Films

Micromachines ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 822
Author(s):  
Hyo-Jun Joo ◽  
Dae-Hwan Kim ◽  
Hyun-Seok Cha ◽  
Sang-Hun Song
Keyword(s):  
Magnetic Field ◽  
Electron Density ◽  
Conduction Band ◽  
Electron System ◽  
Band Edge ◽  
Conduction Band Edge ◽  
Offset Voltage ◽  
Three Samples ◽  
Dimensional Electron System ◽  
Longitudinal Distance

We measured and analyzed the Hall offset voltages in InGaZnO thin-film transistors. The Hall offset voltages were found to decrease monotonously as the electron densities increased. We attributed the magnitude of the offset voltage to the misalignment in the longitudinal distance between the probing points and the electron density to Fermi energy of the two-dimensional electron system, which was verified by the coincidence of the Hall voltage with the perpendicular magnetic field in the tilted magnetic field. From these results, we deduced the combined conduction band edge energy profiles from the Hall offset voltages with the electron density variations for three samples with different threshold voltages. The extracted combined conduction band edge varied by a few tens of meV over a longitudinal distance of a few tenths of µm. This result is in good agreement with the value obtained from the analysis of percolation conduction.

Size-Dependent Valence and Conduction Band-Edge Energies of Semiconductor Nanocrystals

ACS Nano ◽  
2011 ◽  
Vol 5 (7) ◽  
pp. 5888-5902 ◽  
Author(s):  
Jacek Jasieniak ◽  
Marco Califano ◽  
Scott E. Watkins
Keyword(s):  
Conduction Band ◽  
Semiconductor Nanocrystals ◽  
Band Edge ◽  
Conduction Band Edge ◽  
Size Dependent
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