Study On Optoelectronic Detection Of InAs Nanowire

In this paper, we systematically investigated the optoelectronic detection of InAsnanowire (NW). InAs NW has been widely used as channel materials for radiofrequency devices, ballistic transistors, and biochemical sensors, due to its peculiarelectron accumulation layer, high carrier mobility, Fermi level pinning above the edgeof conduction, and ease of Ohmic contacts. However, most research focuses onelectrical properties of InAs NWs, to the best of our knowledge, no room-temperaturenear-infrared photodetectors having detection wavelength up to1.5um has beenreported. Moreover, InAs NWs are very sensitive to chemical molecules. We alsoinvestigated the effects of atmospheric molecules and different metal nanoparticles onphotoresponsivity of InAs NW photodetectors.In this section, we mainly studied the single InAs NW near-infraredphotodetectors. The single InAs NW field-effect transistors (FETs) have a minimumhysteresis with a high Ion/Ioffratio of105. The Schottky-Ohmic contacted InAs NWphotodetectors have a high photoresponsivity, which is threshold larger than that ofOhmic-Ohmic contacted ones. We also studied the effects of metals nanoparticlesdecoration, atmospheric molecules, and HfO2passivation layer on photoresponse ofInAs NW photodetectors. The on-current and photocurrent decreased when thedetectors exposed to atmospheric molecules. This is mainly due to the charge transferand energy band change. The metal nanoparticles decorated InAs NW photodetectorshave a relative larger photoresponsivity than the original ones. To suppress thenegative effects of surface defects and atmospheric molecules, a new photodetectorswith half-wrapped top-gate were introduced in this section.Although the InAs NW has superior optoelectronic properties, it has very lowIlight/Idarkratio. A new photodetectors based on grapheme/InAs NW Schottky junctionswere introduced in this section. The Fermi level of graphene can be modulated byback-gated bias due to the2dimensional nature of graphene. So, the height ofSchottky junction and injection of carrier can be adjusted by the back-gated voltage.The graphene/InAs NW Schottky near-infrared photodetectors have a large Ilight/Idark ratio of500, which is much large than that of single InAs NW near-infraredphotodetectors and graphene near-infrared photodetectors.As photosensitive materials, a new type low-dimensional material-MoS2wasintroduced in this section. The single or multilayer MoS2has energy band-gap rangingfrom1.2eV to1.8eV. Although the MoS2is very sensitive to light, it has low lightabsorption. To enhance the light absorption, the MoS2photodetectors were decoratedwith plasmonic nanoparticles.