Hi Bernd,

I talked to Chris, and so we are both on board.  We will provide you with 
some spin-LED's for your initial measurements.  As I indicated on the 
phone, I do not think that these are particularly suitable for ultrafast 
measurements, but you should be able to test everything out.  If things 
look promising, we can talk about designing an optimal structure.

As far as I am concerned, you should feel free to attempt any electrical 
pump - optical probe or optical pump- electrical probe measurement with 
these devices.  As you are probably aware, I am avoiding virtually all 
optical pump/ optical probe measurements out of a tacit agreement with 
David.  (The exception is one measurement that Scott Crooker is doing).

We have plenty of unbonded devices, and these are what I will send.  They 
are 300 micron diameter mesas, with a 150 micron gold pad deposited through 
a shadow mask.  The position and shape of the gold pad can be somewhat 
irregular, but they have worked quite well.   They will be annealed here at 
250 C.    You can raise the temperature to 150 - 170 C to In bond them to a 
sample holder.  The top contact will have to be wire-bonded.   We will 
prepare a packet with some characteristic J-V curves.  Generally speaking, 
if the J-V looks normal and it emits light, then it will work.  They are 
rather robust provided that the leads are not reversed.  You can use 100 mA 
with the Schottky reverse-biased and the p-n forward biased.  A quick check 
in perp. field is advisable.  Also, be aware that the optimal conditions at 
low temperature are strongly bias-dependent.

We will try to organize things on Thursday to send to you.  Since we have 
lots of unbonded devices.  We will send you a few devices each from both QW 
and bulk detectors.

-Paul



Paul Crowell
Associate Professor of Physics
University of Minnesota
School of Physics and Astronomy
116 Church St. SE
Minneapolis, MN 55455
Phone:  612-624-4828
Fax:  612-624-4578
crowell@physics.umn.edu
http://www.physics.umn.edu/groups/fastspin/