Extremely efficient multiple electron-hole pair generation in carbon nanotube photodiodes.
We observed highly efficient generation of electron-hole pairs due to impact excitation in single-walled carbon nanotube p-n junction photodiodes. Optical excitation into the second electronic subband E22 leads to striking photocurrent steps in the device I-V(SD) characteristics that occur at voltage intervals of the band-gap energy E(GAP)/e. Spatially and spectrally resolved photocurrent combined with temperature-dependent studies suggest that these steps result from efficient generation of multiple electron-hole pairs from a single hot E22 carrier. This process is both of fundamental interest and relevant for applications in future ultra-efficient photovoltaic devices.
Gabor
Nathaniel M
NM
Laboratory of Atomic and Solid-State Physics, Cornell University, Ithaca, NY 14853, USA. nmg32@cornell.edu
Zhong
Zhaohui
Z
Bosnick
Ken
K
Park
Jiwoong
J
McEuen
Paul L
PL
D004560:Electricity; D004583:Electrons; D036103:Nanotechnology; D037742:Nanotubes, Carbon; D055095:Optics and Photonics; D017785:Photons; D013696:Temperature
D037742:Nanotubes, Carbon