Infrared photodetectors in heterostructure nanowires.

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