Bulletin of the American Physical Society
APS March Meeting 2018
Monday–Friday, March 5–9, 2018; Los Angeles, California
Session B01: Applications: Materials Focus
11:15 AM–2:15 PM,
Monday, March 5, 2018
LACC Room: 150A
Sponsoring Unit: FIAP
Chair: Matthieu Dupre, Univ of California - San Diego
Abstract: B01.00001 : Ultrahigh broad band photoresponse in single Germanium Nanowire photodetectors*
11:15 AM–11:27 AM
(S.N.BOSE NATIONAL CENTRE FOR BASIC SCIENCES)
We have investigated photoconductive properties of single Germanium Nanowires (NWs) in the broad spectral range of 300-1100 nm and in the broadband Near Infra-red spectrum. The peak Responsivity (R) reaches ~107A/W at a minimal bias of 2V at λ=850 nm. In NWs with diameter ranging from 30 nm to 90 nm, R lies in the range 105-107A/W. The NWs grown by Vapor-Liquid-Solid mechanism can detect upto ~ 10-15 W, with Detectivity ~1013 cmHz1/2/W. In this report we discuss the likely origin of the ultra large R that may arise from a combination of various physical effects which are (a) Ge/GeO2 interface states which act as “scavengers” of electrons from the photo-generated pairs, leaving the holes free to reach the electrodes, (b) Schottky barrier (~0.2 -0.3 eV) at the metal/NW interface which gets lowered substantially due to carrier diffusion in contact region and (c) photodetector length being small (~few μm), negligible loss of photogenerated carriers due to recombination at defect sites. We have confirmed, from power dependence of the optical gain that there is presence of trap states at the surface region and have estimated the surface trap density ~1013cm-2 s-1 that predominantly lie at the Ge/GeO2 interface.
*Nanomission, Govt. of India
J. C. Bose Fellowship.
The American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics.
1 Physics Ellipse, College Park, MD 20740-3844
Editorial Office 1 Research Road, Ridge, NY 11961-2701 (631) 591-4000
Office of Public Affairs 529 14th St NW, Suite 1050, Washington, D.C. 20045-2001 (202) 662-8700