% Al 0% 0.68% 1.2%

1. % Al 0% 0.68% 1.2% Aluminum-Doped Cadmium Selenide NanocrystalsWayne L. Gladfelter, University of Minnesota, DMR 0908629 Semiconductor nanocrystals (NCs) are finding applications in a variety of opto-electronic devices. As with bulk semiconductors being able to control the electrical properties is critical for optimal device performance. Al-doped CdSe NCs were synthesized in a 3-step process in which small nuclei (~2 nm diam) of CdSe were prepared, exposed to an Al precursor and covered with a CdSe shell. Analyzing the Al content as a function of etching time established that Al was distributed throughout the NCs. Transistors made using the Al-doped CdSe NCs displayed a characteristic shift in the turn-on voltage as the Al concentration increased. The turn-on voltage of transistors made using Al-doped CdSe nanocrystals (diam = 3.4 nm) was found to be proportional to the conduction band energy (ECB) minus the Fermi energy (EF). Increasing the Al concentration increased the EF, which caused the turn-on voltage to decrease.

2. Students Work at Univ. of Duisburg-Essen Wayne L. Gladfelter, University of Minnesota, DMR 0908629 The NSF-MWN grant provided our students with the opportunity to work in Germany at the University of Duisburg-Essen with our collaborator, Prof. Markus Winterer. U of M undergrads Ian Ma and Michael Sun spent two months at UDE during the summer of 2011 working on doped metal oxide nanoparticles. U of M graduate student AyaskantaSahu spent time with Winterer's group collecting and analyzing extended X-ray adsorption fine structure (EXAFS) data on silver-doped CdSenanocrystals. Prof. Wayne Gladfelter visited UDE in May, 2011 to review projects, present a seminar and serve on the PhD thesis defense committee for RuzicaDjenadic. U of M undergrad Michael Sun and UDE grad student Udo Dörflerworking on the chemical vapor synthesis of Al-doped ZnOnanocrystals. U of M undergrad Ian Ma and Prof. Markus Winterer at the farewell group meeting at the UDE.