Optical communication between NW nodes

The deliverable will be based on the Task 1.1Interconnectivity by light: Step-by-step implementation of assemblies of III-V NW based absorbers and emitters starting with one pair and then extending. We will use already existing, reliable n-i-n InP NWs as detectors. These will be placed using a Scanning Electron Microscope (SEM) nanoprobe. As emitters we will use an InP quantum dot grown in an Al0.3In0.7P NW. We will experimentally verify the functionality by both electrical measurements of the circuit and measurements of light fields using local light field sensitive photoemission electron microscopy (PEEM)28 and scanning probes coupled with high resolution optical microscopy and lasers. For the III-V nanopillar (made by nanolithography and dry etching) spiking absorbers and emitters, we will design within the epilayer stacks: i) n-i-n AlAs/GaAs/AlAs DBQW layer stacks as detector and spike generators, ii) p-i-n layer GaAs/AlGaAs as emitter/cladding layers. Optical simulations will use Finite-difference methods, and real-time Green's functions (nextnano software) to simulate epilayers. We will use III-Vs on GaAs and on Ge-Si substrates (wafer bonding of III-Vs to Si will be also targeted). We will verify the functions of electrically pumped nanopillars by static electrical measurements (current-voltage), static photoresponse of the detector, micro-electroluminescence to determine light-current and emission characteristics. We will derive from first principles the non-linear differential rate equations governing the spiking neurons with light emitting and detector functions. Models will be used in WPs 3 and 4 for neural network system simulations.