Growth of ultrahigh-density quantum-confined germanium dots on SiO2 thin films

Abstract

The spontaneous formation of nanometric and highly dense (∼3×1012cm−2) Ge droplets on thin SiO2 film on Si(001) is investigated by scanning tunneling microscopy and spectroscopy. Ge dots have been grown by depositing Ge on the clean SiO2 surface at room temperature and then annealing the sample at 500°C. Ge dots appear to be free of germanium oxides and characterized by a flat surface with the onset of {113} faceting. I-V curves show that they have an energy gap of approximately 1.8eV, well above that of bulk Ge. Fabrication of nanometer-sized, highly dense pure Ge droplets is very promising for nanoelectronics applications.