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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|
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