Research Highlights 2001-2010 – N. Pelekanos PhD 1991: Brown Univ. (USA) Post-docs: CEA/Grenoble, CNET Lannion, Max-Planck Stuttgart 1994-2001: CEA/Grenoble 2001-2010: FORTH & Univ. of Crete Novel optoelectronic devices - GaAs Nitrides: Towards improved optoelectronic devices Nanowire solar cells Piezoelectric quantum dots: InAs (GaN) Funding: EC, ΓΓΕΤ, ΥΠΕΠΘ,..., 2,9 million Euros FORTH Microelectronics Research Group Univ. of Crete

Nitrides: Highlights Eliminate internal fields for better blue lasers Superior p-type contacts Integrated HEMT on LED Polarization engineering on InAlGaN/GaN quantum wells can give zero-field nitride optoelectronic devices. But, the optoelectronic quality of InAlGaN has to be further improved. Cr/Au vs Ni/Au LED fabrication IST QN-Laser, IST QN-Laser II G. Dialynas et al. JAP 2008 F. Kalaitzakis, APL 2007 NMP GaNano

Novel optoelectronic devices: Highlights Polariton LEDs and Lasers Tunable laser diodes Piezoelectric laser diodes p-side CB B1 B2 VB Jth(111) < Jth(100) T=235K -S. Tsintzos, Nature 2008 -RT operation, S. Tsintzos, APL 2009. G. Deligeorgis, APL 2007 IST Tune-laser APL 2002, APL 2003 20nm tuning at low T, 5nm tuning at 300K

Piezoelectric quantum dots: Highlights V InAs (211)B QDs Reference QW InAs QDs G. Dialynas, JAP 2010 + + + + + - - - - - - - - - - - - - + e h G. Dialynas, to be submitted

Piezoelectric quantum dots: Highlights Very small FSS. Promising for sources of entangled photons Single dot spectroscopy Single photon emission; possibility for high-T operation Anti-binding biexciton energy S. Germanis, APL 2011

Project: III-V Nanowires for high efficiency Solar cells Solar Innovation 2010 Award by Commissariat a l’ Energie Atomique 3 year project Why Nanowires for Solar Cells? Potential for lower cost and high efficiency: - enhanced light absorption, less material utilization - no need for lattice matching, easier choice of substrate & more freedom in heterostructure design - direct path for charge transport “nanowire solar cells”