Wonjong Kim
Scaling-up nanowire devices: a systematic approach for testing and operation
École polytechnique fédérale de Lausanne
Our research interests are centered on investigation of novel semiconductor nanostructure combinations, using nanowires, which are filamentary crystals with having a very high length to diameter ratio. From fundamental point of view, semiconductor nanowires exhibit many interesting properties different from bulk materials. In addition, they are attractive building blocks for the assembly of novel nano-electronic and nano-photonic system as well as quantum communication and computing. The inherent small dimension of nanowire interface allows for strain relaxation in hetero-epitaxy system which enables us to combine high performance III-V materials in the standardized silicon CMOS process. Specifically, we are working on the integration of self-catalyzed GaAs NWs on patterned silicon substrates using Molecular Beam Epitaxy system, which can circumvent the gold contamination issues in silicon.
Fig.1 SEM image taken at a 20 ° tilt from normal showing highly uniform GaAs nanowire arrays
NW arrays with tunable diameters, lengths and inter-wire spacing are a very promising platform for future NW array based applications where we need to engineer the device properties using different materials, combinations and forms of hetero-structures. Despite demonstrating potential advantages of NWs and NW-based technologies, there are still many challenges for their transfer from the laboratory to market-ready products. Main objective of this project is increasing functionality of III-V NW arrays on patterned silicon substrates. Doping incorporation characteristics on NW arrays that involve the study of the doping influence on the NW growth itself, doping uniformity, doping level and doping availability in hetero-structure will be systematically investigated. In addition, automatized NW characterization platform will be studied in cooperation with Imina Technologies. Within INDEED network, including academia and the industry, we aim to bring the full integration of III-V NWs on silicon.
