GaAs nanowires (NWs) are promising advanced materials for the development of high performance photodetectors in the visible and infrared range. In this work, we optimize the epitaxial growth of GaAs NWs compared to conventional procedures, by introducing a novel two-steps growth method that exhibits an improvement of the resulting NW aspectratio and an enhancement of the NW growth rate. Moreover, we investigate the contactless manipulation of NWs using non-uniform electric fields to assemble a single GaAs NW on conductive electrodes, resulting in assembly yields above 90site and an alignment yields of around 95 The electrical characteristics of the dielectrophoretic contact formed between the NW and the electrode have been measured, observing that the use of n-type Al-doped ZnO (AZO) as electrode material for NW alignment produces Schottky barrier contacts with the GaAs NW body. Moreover, our results show the fast fabrication of diodes with rectifying characteristics due to the formation of a low-resistance contact between the Ga catalytic droplet at the tip of the NW and the AZO electrode. The current-voltage measurements of a single GaAs NW diode under different illumination conditions show a strong light responsivity of the forward bias characteristic mainly produced by a change on the series resistance.
|Title of host publication||Optical Sensing, Imaging, and Photon Counting|
|Subtitle of host publication||Nanostructured Devices and Applications 2017|
|Editors||Manijeh Razeghi, Oleg Mitrofanov, Jose Luis Pau Vizcaino, Chee Hing Tan|
|Publisher||Society of Photo-Optical Instrumentation Engineers|
|Publication status||Published - 19 Sept 2017|
|Name||Proceedings of SPIE|