Nachricht von Paul Crowell (s.u.) . Wir werden Proben für die gepulste Injektion bekommen.

Bernd

-------- Ursprüngliche Nachricht -------- Betreff: Spin LED's Datum: Tue, 10 Aug 2004 23:55:43 -0500 Von: Paul Crowell crowell@physics.umn.edu An: bernd.beschoten@physik.rwth-aachen.de CC: palms001@umn.edu

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/