Materials Science

Small and Sensitive

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Science  10 Feb 2006:
Vol. 311, Issue 5762, pp. 743-745
DOI: 10.1126/science.311.5762.743d

Fiber optic systems offer significant bandwidth and efficiency advantages as compared with traditional current-bearing wires. However, shifting the carrier from electrons to photons requires the development of alternative switch and detector technologies. Recently, indium phosphide nanowires were investigated for potential use as integrated detectors in photonic devices and optical switches.

Pettersson et al. have prepared more complex heterostructures and analyzed their response across a range of infrared wavelengths. The authors grew indium arsenide (InAs) wires with a core region including either 15 or 35% phosphorus, and then incorporated them into photodetection devices. The energy gap between the InAs and InAsP conduction bands strongly reduced the dark current (that is, the current measured when the wires are not exposed to light), and the spectral response could be modulated by the extent of phosphorus doping. Moreover, light that was polarized parallel to the wire induced 10 times more current than orthogonally polarized light, a property attributed to the large dielectric contrast between the nanowires and surrounding medium. The results suggest considerable promise for these structures as efficient infrared polarization-sensitive detectors in the 0.65- to 1.4-eV energy range. — MSL

Nano Lett. 10.1021/nl052170l (2006).

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