Numerical models of potential in local density functional method

1991 ◽  
Vol 31 (6) ◽  
pp. 851-856 ◽  
Author(s):  
V. A. Nasluzov ◽  
G. L. Gutsev ◽  
V. K. Gryaznov
Keyword(s):  
Density Functional ◽  
Local Density ◽  
Numerical Models ◽  
Density Functional Method ◽  
Functional Method ◽  
Local Density Functional

Theoretical Investigations of the Energy Levels of Defects in Germanium

2005 ◽  
Vol 108-109 ◽  
pp. 697-702 ◽  
Author(s):  
R. Jones ◽  
A. Carvalho ◽  
J. Coutinho ◽  
Vitor J.B. Torres ◽  
Sven Öberg ◽  
...  
Keyword(s):  
Density Functional ◽  
Local Density ◽  
Energy Levels ◽  
Density Functional Method ◽  
Functional Method ◽  
Band Gaps ◽  
Donor And Acceptor ◽  
Theoretical Investigations ◽  
Local Density Functional ◽  
Experimental Values

The donor and acceptor levels of defects in Ge as well as in Si are found using a local density functional method applied to large H-terminated defective clusters. The surfaces of the clusters are modified so that their band gaps are aligned with experimental values. It is shown that the resulting energies of the first donor and acceptor levels are within about 0.2 eV of the experimental values.

AN INVESTIGATION OF THE DOPING PROPERTIES OF ZnSe NANOCRYSTALS

2011 ◽  
Vol 25 (27) ◽  
pp. 3655-3662
Author(s):  
XIYING MA ◽  
JINWEI SONG
Keyword(s):  
Density Functional ◽  
Local Density ◽  
Density Functional Method ◽  
Functional Method ◽  
Acceptor Impurity ◽  
Deep Acceptor ◽  
Deep Acceptor Level ◽  
P Type ◽  
Cl Atom ◽  
Znse Nanocrystals

This paper investigates the properties of ZnSe nanocrystals doped with single N , P or As atoms (for p-type doping) or single F , Cl or Br atoms (for n-type doping). The crystals are simulated using the local density functional method. Structures doped with an N or Cl atom remained symmetrical, but some distortion appeared with the other dopants. We found that N is the most efficient acceptor impurity for p-type doping, while Cl is the most suitable impurity for n-type doping. In the case of heavy p-type doping, complex defects such as N Se – Zn – V Se and N Se – Zn int easily form in the structure. We found that N Se – Zn – V Se produces a deep acceptor level in the bandgap, while N Se – Zn int produces a compensating donor level in p-type doping. The latter is the main reason for that p-type ZnSe is difficult to achieve. This study is useful to researchers investigating p- and n-type doping as well as device manufacturers.

The Influence Mechanism of Halogen Ion on the Temperature Quenching Performance of Sr2SiO4:Eu Phosphors

2016 ◽  
Vol 16 (4) ◽  
pp. 3990-3993 ◽  
Author(s):  
Lingli Wang ◽  
Haiyong Ni ◽  
Qiuhong Zhang ◽  
Fangming Xiao
Keyword(s):  
Band Structure ◽  
Density Functional ◽  
Local Density ◽  
Density Functional Method ◽  
Luminescent Properties ◽  
Functional Method ◽  
Density Approximation ◽  
Luminescent Intensity ◽  
Temperature Quenching ◽  
Influence Mechanism

The luminescent properties of Sr2SiO4:Eu phosphors synthesized with and without flux have been investigated. With the co-dopation of NH4Cl, the luminescent intensity of Sr2SiO4:Eu is increased and the temperature quenching property is improved. The effect of NH4Cl is analyzed not only from the crystallinity of the Sr2SiO4 crystal but also the band structure of Sr2SiO4 host, which is calculated by density functional method with the local density approximation.

First-Principles Study of Photoexcited Defects in Polysilane Chains

1990 ◽  
Vol 209 ◽  
Author(s):  
J. W. Mintmire ◽  
R. C. Mowrey ◽  
D. W. Brenner ◽  
B. I. Dunlap ◽  
C. T. White
Keyword(s):  
First Principles ◽  
Optical Materials ◽  
Density Functional ◽  
Model Simulation ◽  
Local Density ◽  
Density Functional Method ◽  
Functional Method ◽  
Charge Carriers ◽  
Bond Scission ◽  
Total Energies

ABSTRACTOrganopolysilane materials have recently demonstrated potential technological importance as positive photoresists, photoconductors, and nonlinear optical materials. Many of the technological applications of these materials depend intimately on the photoexcitation process in these materials, possibly resulting in either bond scission or the creation of mobile charge carriers. Herein we present some preliminary results of a model simulation of the photoexcitation process in oligomeric polysilane chains using a recently developed first-principles local-density functional method for the calculation of electronic structures,total energies, and gradients of the total energy with respect to nuclear coordinates.

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