 
Outputbandstructure
The output of potential, valence and conduction bands is controlled by this
keyword.
!!
$outputbandstructure
optional !
destinationdirectory
character
required !
conductionbandnumbers
integer_array
optional !
valencebandnumbers
integer_array
optional !
!
potential
character
optional !
builtinpotential
character
optional !
electricfield
character
optional !
bandgap
character
optional !
!
outputgridposition
double_array
optional !
outputgridpositionoctant
character
optional !
$end_outputbandstructure
optional !
!!
Syntax:
destinationdirectory
=
band_structure/
= /MOSFET/band_structure/
Name of directory to which the files should be written. Must exist
and directory name has to include the slash (\ for DOS and / for UNIX). Must
be the first specifier.
conductionbandnumbers = 1 2 3
Numbers of conduction band edges that are put out (1,
..., max_num_cbbands ). The numbering corresponds
to the original numbering in the database. If a band is
split because of strain, there will be several columns in the output file
for all subbands.
1 = Gamma
band
2 = L band
3 = X band
If one does not want to print any conduction band, one can put this line
into comments or delete it.
valencebandnumbers = 1 2 3
Numbers of valence bands that are put out (1,
..., max_num_vbbands ).
1 = heavy hole band
2 = light hole band
3 = splitoff hole band
If one does not want to print any valence band, one can put this line into
comments or delete it.
potential = yes
=
no
Flag whether to put out the electrostatic potential in units of [V].
The electrostatic potential is the solution of the Poisson equation.
builtinpotential = yes
=
no
Flag whether to put out the electrostatic builtin potential in units of [V].
Two builtin potentials are written out:
The electrostatic
builtin potential is the solution of the Poisson equation in equilibrium.
The classical electrostatic builtin potential is the solution of the Poisson equation
in equilibrium using only classical densities, i.e. ignoring any quantum
mechanical densities. (This potential is used as a start value for the
quantum mechanical calculations.)
==> potential_built_in_cl_1D.dat
==> potential_built_in_1D.dat
Additionally, the starting value (initial guess) of the electrostatic
potential is written out.
Currently, this initial guess is determined depending on the local doping
concentration.
==> potential_initial_guess_1D.dat
electricfield = yes
=
no
Flag whether to output the electric field in the file
electric_field.fld .
Units: [kV/cm] ( = 1d5 [V/m] )
The electric field is defined on the material grid points, i.e. on the
points lying exactly in the middle of the "physical" grid points where the
electrostatic potential is defined.
The electric field is calculated as the negative gradient of the
electrostatic potential. (CHECK: Is this correct? Shall we output or call
it the displacement D instead?)
bandgap = yes ! (default for
1D simulations)
=
no ! (default for 2D/3D
simulations)
Flag whether to put out the band gap in the file
BandGap1D.dat .
Units: eV
The minimum of all conduction band edges (E_c_min ), the maximum
value of all valence band edges (E_v_max ), and the
corresponding band gap is part of the output (E_gap_min ).
Also, the band gaps for the Gamma (E_gap_Gamma ), L (E_gap_L )
and X (E_gap_X ) band edges are printed out.
If bands are split due to strain, for each split band, the band gap is
printed out. They are labeled with _a , _b ,
_c , _d .
For 1D simulations, all data is contained in this file:
band_structure/BandGap1D.dat
For 2D and 3D simulations, for each a separate file is printed out.
They are called: E_c_min*, E_v_max*, E_gap_min*, E_gapGamma*, E_gapL*,
E_gapX*
For 1D simulations, all data is contained in this file:
band_structure/BandGap1D.dat
outputgridposition =
10d0 !
[nm] 1D: x = 10 nm
= 10d0 20d0 !
[nm] 2D: (x,y) = (10 nm, 20 nm)
= 10d0 20d0 0d0 ! [nm]
3D: (x,y,z) = (10 nm, 20 nm, 0 nm)
Here, one can specify a grid point (i,j,k) where output like band edges,
potential, densities, ... are written out.
This also works together with a sweep (e.g. voltage sweep, magnetic field
sweep).
outputgridpositionoctant = left !
1D: octant 1, i
(default for 1D)
= right !
1D: octant 2, i+
= lowerleft
! 2D: octant 1, (i,j) (default for 2D)
= lowerright
! 2D: octant 2, (i+,j)
= upperleft
! 2D: octant 3, (i,j+)
= upperright
! 2D: octant 4, (i+,j+)
= bottomlowerleft ! 3D: octant 1,
(i,j,k) (default for 3D)
= bottomlowerright ! 3D: octant 2, (i+,j,k)
= bottomupperleft ! 3D: octant 3,
(i,j+,k)
= bottomupperright ! 3D: octant 4, (i+,j+,k)
= toplowerleft !
3D: octant 5, (i,j,k+)
= toplowerright ! 3D:
octant 6, (i+,j,k+)
= topupperleft !
3D: octant 7, (i,j+,k+)
= topupperright ! 3D:
octant 8, (i+,j+,k+)
This is necessary for properties that are discontinuous at material
interfaces.
If there is an interface at the grid point outputgridposition,
then one has to specify for which octant the output should refer to.
(In 3D there are 8 octants, in 2D there are four "octants", and in 1D there are
two "octants".
Output
Bandedges:
Filename:
cb 1D_Gamma_ind000.dat, cb 1D_L_ind000.dat
, cb 1D_X_ind000.dat
vb 1D_hh_ind000.dat
, vb 1D_lh_ind000.dat,
vb 1D_so_ind000.dat 
cb
vb 


indicates if conduction (cb)
or valence (vb) band is contained 

_Gamma 

name of band (Gamma, L, X, heavy hole,
light hole, splitoff hole) 


_ind000 
number of voltage step corresponding to
this output file (only if voltage sweep is turned on) 
Structure:
position[nm] 
X_bandedge[eV]_a 
X_bandedge_b[eV] 
0.000000E+00 
0.000000E+00 
0.000000E+00 
Position in space [l0] 
Subband 1 [eV] 
Subband 2 [eV] 
Remark:
Due to strain the bands with degenerate minima split into several subbands.
These subbands are listed in different columns (e.g. in silicon for the X band
(band no. 3) if strain is present, the band edges split.).
In 1D simulations, an additional files exists: BandEdges1D.dat
It contains all band edges and all Fermi levels that should be printed
out in one output file.
Potential:
Filename:
potential1D_ind001.dat 

_ind000 
number of voltage step corresponding to
this output file (only if voltage sweep is turned on) 
Structure:
distance: 
pot: 
0.000000E+00 
0.000000E+00 
position in space [nm] 
electrostatic potential [V] 
Classical builtin potential for the device
First, the Poisson equation is solved in equilibrium, using on
classical densities, i.e. without quantum mechanics.
The resulting electrostatic potential is called the builtin potential of the
device for a classical density.
==> potential_built_in_cl_1D.dat
Builtin potential for the device
Then, the Poisson equation is solved again in equilibrium, using
either classical or quantum mechanical densities, or a combination of both,
depending on the input file).
The resulting electrostatic potential is called the builtin potential of the
device.
In case, no quantum mechanical densities are involved, the builtin potential is
identical to the classical builtin potential.
==> potential_built_in_1D.dat
