Nano Archive

Infrared photodetectors in heterostructure nanowires

Pettersson, H and Tragardh, J and Persson, AI and Landin, L and Hessman, D and Samuelson, L (2006) Infrared photodetectors in heterostructure nanowires. NANO LETTERS, 6 (2). pp. 229-232.

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We report on spectrally resolved photocurrent measurements on single self-assembled nanowire heterostructures. The wires, typically 3 mu m long with an average diameter of 85 nm, consist of InAs with a 1 mu m central part of InAsP. Two different sets of wires were prepared with phosphorus contents of 15 +/- 3% and 35 +/- 3%, respectively, as determined by energy-dispersive spectroscopy measurements made in transmission electron microscopy. Ohmic contacts are fabricated to the InAs ends of the wire using e-beam lithography. The conduction band offset between the InAs and InAsP regions virtually removes the dark current through the wires at low temperature. In the optical experiments, interband excitation in the phosphorus-rich part of the wires results in a photocurrent with threshold energies of about 0.65 and 0.82 eV, respectively, in qualitative agreement with the expected band gap of the two compositions. Furthermore, a strong polarization dependence is observed with an order of magnitude larger photocurrent for light polarized parallel to the wire than for light polarized perpendicular to the wire. We believe that these wires form promising candidates as nanoscale infrared polarization-sensitive photodetectors.

Item Type:Article
Subjects:Material Science > Functional and hybrid materials
Physical Science > Nano objects
Physical Science > Photonics
ID Code:3692
Deposited By:Farnush Anwar
Deposited On:22 Jan 2009 14:01
Last Modified:29 Jan 2009 13:37

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