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We report a systematic study of time-resolved and power-dependent photoresponse in high-efficiency germanium quantum dot photodetectors (Ge-QD PDs), with internal quantum efficiencies greater than 100% over a broad wavelength, reverse bias, and incident power range. Turn-on and turn-off response times (τon and τoff) are shown to depend on series resistance, bias, optical power, and thickness (WQD) of the Ge-QD layer, with measured τoff values down to ∼40 ns. Two different photoconduction regimes are observed at low and high reverse bias, with a transition around −3 V. A transient current overshoot phenomenon is also observed, which depends on bias and illumination power.
American Institute of Physics
Publication date: 
15 Oct 2012

Pei Liu, S Cosentino, Son T Le, S Lee, D Paine, A Zaslavsky, D Pacifici, S Mirabella, M Miritello, I Crupi, A Terrasi

Biblio References: 
Volume: 112 Issue: 8 Pages: 083103
Journal of Applied Physics