European quantum dot researchers awarded prizes
Dieter Bimberg at the Technical University of Berlin, and Zhores Alferov at the Ioffe Institute, Russia (winner of the 2000 Nobel prize for physics) and other co-workers have received the State Prize of Science and Technology 2001 from the Russian Federation for their work on quantum dots and quantum dot lasers.
"I am deeply honoured by this prestigious award as it is always gratifying to receive external recognition for pioneering research," said Bimberg. "Of course, this award reflects our effort over the last few years, but there are still many exciting discoveries to be made in the area of quantum dots. Our participation in the EU s DOTCOM project will help to accelerate these discoveries and identify the commercial possibilities for these structures."
The other award recipient was Sven Rodt from the Technical University of Berlin who received the best student paper award at the International Semiconductor Physics Conference, held in Edinburgh in early August, for his presentation Antibinding excitons in self-organised InAs/GaAs quantum dots. This biannual conference is one of the foremost conferences on semiconductor physics and the accolade is, therefore, prestigious for any young researcher.
QD lasers power past the 10 W mark
Bimberg s team have made the first reporting of a quantum dot (QD) laser that operates with an output power of over 10 W. (Electronics Letters 2002 38(16) 883). The device was grown by MOCVD on a GaAs substrate. The active region consisted of six repeats of an InGaAs QD layer capped with a 30 nm GaAs layer. The laser emitted at 1135 nm with a threshold current of 650 mA and in CW operation had a maximum output power of 4.7 W at 12 A drive current.
Under quasi-CW operation (50 µs pulses with 50 Hz repetition frequency) a maximum power output of 11.7 W was achieved at 21.5 A drive current. Output power was limited by catastrophic optical damage to the laser facets when the power density reached 19.5 MW cm-2 A lifetime exceeding 3000 hours was possible by reducing the drive current to operate the laser at 1.5 W output power.
