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In this work, ultrathin amorphous Ge films (2 to 30 nm in thickness) embedded in SiO2 layers were grown by magnetron sputtering and employed as proficient light sensitizer in photodetector devices. A noteworthy modification of the visible photon absorption is evidenced due to quantum confinement effects which cause both a blueshift (from 0.8 to 1.8 eV) in the bandgap and an enhancement (up to three times) in the optical oscillator strength of confined carriers. The reported quantum confinement effects have been exploited to enhance light detection by Ge quantum wells, as demonstrated by photodetectors with an internal quantum efficiency of 70%.
Springer New York
Publication date: 
1 Dec 2013

Salvatore Cosentino, Maria Miritello, Isodiana Crupi, Giuseppe Nicotra, Francesca Simone, Corrado Spinella, Antonio Terrasi, Salvatore Mirabella

Biblio References: 
Volume: 8 Issue: 1 Pages: 128
Nanoscale research letters