Sergio Pineda edited section_Photodectors_and_Sensors_Spectrosocopy__.tex  about 9 years ago

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\section{Photodectors and Sensors}  Spectrosocopy and imaging are important to provide insight into analysis, and characterization of a chemical physical processes. \cite{Dai_2014}Furthermore, optical data links, such as vertical cavity surface emitting lasers, rely on photodectors on the receiving end to be sensitive enough to detect different frequencies of light.\cite{Seyedi_2014}  Therefore improvements of photodectors and other sensors are always desired. Peng and coworkers have recently, developed single GaAs nanowires as microscopic coherent THz sensors.\cite{Peng_2015} These single GaAs nanowire detectors were fabricated using a direct laster lithographic technique and were even used as a spectrometer to measure the transmission spectrum of a 290 GHz low pass filter. Dai and coworkers have developed a nanowire photodetector using a GaAs core and AlGaAs shell nanowires.\cite{Dai_2014} In typical III-V NW the large density of surface states pin the surface fermi energy, limiting carrier mobility. These surface states were "passivated" by placing a "shell" on top. The GaAsAl shell and GaAs was found to be significantly more sensitive as a photodetector than the GaAs nanowire alone. Low dark current and high photoresponsivity was found in the range of 300-890 nm.