🚀 go-pugleaf

  Howdy,

  Does anybody know where to get simulation programs to do bandstructure
and carrier density calculations for hetrostructures, preferably for ones
containing several stacked quantum wells ? We have one written here in HUT, 
but it only handles one half-well, not a set of complete wells ( a super-
lattice) or eg. two interacting wells.

  Thanks,
           Mikko Kiviranta


  

In article <1992Nov5.081229.2190@nntp.hut.fi> you write:
>
>  Howdy,
>
>  Does anybody know where to get simulation programs to do bandstructure
>and carrier density calculations for hetrostructures, preferably for ones
>containing several stacked quantum wells ? We have one written here in HUT, 
>but it only handles one half-well, not a set of complete wells ( a super-
>lattice) or eg. two interacting wells.
>
>  Thanks,
>           Mikko Kiviranta
>

I am interested in your model -- can I have a copy of it ?

For stacked quantum wells, I am aware of several papers in the 
literature that describes how to calculate the band structure.
If you are interested in heterostructure device simulation you should
consult the software from Purdue University (Mark Lundstrom's group)
called PUPHS.  This program can (I think) calculate carrier
densities in a heterostructure.   If you need more information on 
the contact e-mail address and bibliography please send me an
e-mail (mouli@emx.cc.utexas.edu).

Chandramouli.                                 mouli@emx.cc.utexas.edu
---------------------------------------------------------------------
Microelectronics Research Center in the University of Texas at Austin
---------------------------------------------------------------------

In article <83220@ut-emx.uucp> vcm@ccwf.cc.utexas.edu (V. Chandramouli) writes:

>In article <1992Nov5.081229.2190@nntp.hut.fi> you write:
>>
>>  Howdy,
>>
>>  Does anybody know where to get simulation programs to do bandstructure
>>and carrier density calculations for hetrostructures, preferably for ones
>>containing several stacked quantum wells ? We have one written here in HUT, 
>>but it only handles one half-well, not a set of complete wells ( a super-
>>lattice) or eg. two interacting wells.
>>
>>  Thanks,
>>           Mikko Kiviranta
>>

>I am interested in your model -- can I have a copy of it ?

>For stacked quantum wells, I am aware of several papers in the 
>literature that describes how to calculate the band structure.
>If you are interested in heterostructure device simulation you should
>consult the software from Purdue University (Mark Lundstrom's group)
>called PUPHS.  This program can (I think) calculate carrier
>densities in a heterostructure.   If you need more information on 
>the contact e-mail address and bibliography please send me an
>e-mail (mouli@emx.cc.utexas.edu).

>Chandramouli.                                 mouli@emx.cc.utexas.edu
>---------------------------------------------------------------------
>Microelectronics Research Center in the University of Texas at Austin
>---------------------------------------------------------------------

If Mikko is talking about a simulation program I wrote (or anyway), I must 
say that itcan calculate structures of several heterojunctions. But in order 
to do thatyou have to recompile the program for each specific structure (and 
convergence is not obvious). 

Other facts about my program:

- It is an interactive simulation program for the conventional HEMT- or
  MODFET-structures (AlGaAs). You get the sheet carrier concentration in the 
  channel as a function of the gate voltage.

- It solves the Schroedinger's and the Poisson's equations self-
  consistently using the finite difference method described in 'Numerical 
  Recipes in C'. 

- Initial guess is very important for convergence. When program is 
  executed it fetches the initial guess from a file. Later the result of 
  previous calculation is always used as an initial guess.

- Setting parameters are: gate voltage, thickness and donor density of doped 
  AlGaAs layer, thickness of the spacer (undoped AlGaAs) layer, 
  acceptor density in substrate (GaAs) and temperature. 

- Only the two lowest subbands are considered.

- Program menus are unfortunately written in finnish.


If you are still interested, email me. I can translate the menus in english 
if you wish.


 ---------------------------------
|                   Kimmo Taskinen|
|           ktaskine@finsun.csc.fi|
|      Electron Physics Laboratory|
|Helsinki University of Technology|
|                      Otakaari 7A|
|                   SF-02150 Espoo|
|                          FINLAND|
 ---------------------------------

>>>>> On 8 Nov 92 18:12:58 GMT, vcm@ccwf.cc.utexas.edu (V. Chandramouli) said:

V.> In article <1992Nov5.081229.2190@nntp.hut.fi> you write:
>
>  Howdy,
>
>  Does anybody know where to get simulation programs to do bandstructure
>and carrier density calculations for hetrostructures, preferably for ones
>containing several stacked quantum wells ? We have one written here in HUT, 
>but it only handles one half-well, not a set of complete wells ( a super-
>lattice) or eg. two interacting wells.
>
>  Thanks,
>           Mikko Kiviranta
>

V.> I am interested in your model -- can I have a copy of it ?

V.> For stacked quantum wells, I am aware of several papers in the 
V.> literature that describes how to calculate the band structure.
V.> If you are interested in heterostructure device simulation you should
V.> consult the software from Purdue University (Mark Lundstrom's group)
V.> called PUPHS.  This program can (I think) calculate carrier
V.> densities in a heterostructure.   If you need more information on 
V.> the contact e-mail address and bibliography please send me an
V.> e-mail (mouli@emx.cc.utexas.edu).
V.> Chandramouli.                                 mouli@emx.cc.utexas.edu
V.> ---------------------------------------------------------------------
V.> Microelectronics Research Center in the University of Texas at Austin
V.> ---------------------------------------------------------------------

This might be relevant:

Here at the IuE we are working, amongst other things, on extending our
device simulator MINIMOS to HEMTs and MODFETs. In order to have a
validation tool against which to gauge pre-release simulations, a
co-worker and I wrote a standalone self-consistent
Schroedinger-Poisson solver which can handle an arbitrary number of
heterolayers. As well as carrier densities and bandstructures, it
works out capacitance-voltage curves, has incomplete donor ionization,
exchange-correlation effects (sort of) and an educated initial guess
for single-well heterostructures. I ought to add as a caveat that the
code (well, my part of it at least) is a typical research product,
i.e. ugly, inefficient and a wonderful example of feet-first
programming. Moreover, it has been used principally to work out C-V
curves for HEMTs, and as such has not had much experience with
superlattices and/or multiple quantum wells.

Still, E-mail me if you are interested.

Cristiano



--

Cristiano Sala                                            sala@iue.tuwien.ac.at
Practice random kindness              and              senseless acts of beauty