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The role of the interface potential on the effective mass of charge carriers is elucidated in this work. We develop a new theoretical formalism using a spatially dependent effective mass that is related to the magnitude of the interface potential. Using this formalism, we studied Ge quantum dots (QDs) formed by plasma enhanced chemical vapour deposition (PECVD) and co-sputtering (sputter). These samples allowed us to isolate important consequences arising from differences in the interface potential. We found that for a higher interface potential, as in the case of PECVD QDs, there is a larger reduction in the effective mass, which increases the confinement energy with respect to the sputter sample. We further understood the action of O interface states by comparing our results with Ge QDs grown by molecular beam epitaxy. It is found that the O states can suppress the influence of the interface potential. From our …
AIP Publishing LLC
Publication date: 
21 Apr 2015

EG Barbagiovanni, S Cosentino, DJ Lockwood, RN Costa Filho, A Terrasi, S Mirabella

Biblio References: 
Volume: 117 Issue: 15 Pages: 154304
Journal of Applied Physics