Berlin 2018 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 19: Quantum dots and wires: Transport properties

HL 19.13: Talk

Tuesday, March 13, 2018, 12:45–13:00, A 151

Electrical characterization of semiconductor nanowires with axial pn-junction — •Cornelia Timm¹, Andreas Nägelein¹, Matthias Steidl¹, Klaus Schwarzburg², Peter Kleinschmidt¹, and Thomas Hannappel¹ — ¹Institute of Physics, TU Ilmenau, Germany — ²Helmholtz Zentrum Berlin, Germany

Semiconductor nanowires are of great interest for applications in future nanoscale optoelectronic devices. For optimal performance it is crucial to understand the precise electrical characteristics of the nanowires, in particular their electrical transport properties.

Here we present resistance profiling along the axial pn-junction of GaAs nanowires. This was probed directly using a 4-tip STM, an advanced technique resulting in a high spatial resolution of the nanowire resistance. Applying a transport model allows for the determination of the doping profiles. As expected we detected a voltage drop at the pn-junction, correlated to the forward bias of the diode. The nonlinear I-V characteristic revealed a reduced differential conductivity at the pn-junction.

Additionally, spatially resolved photoluminescence and cathodoluminescence measurements were conducted to further examine the pn-junction of the GaAs nanowire. The p and n-segment of the nanowire exhibited a different photoluminescence spectrum. Due to the electric field gradient, the photoluminescence intensity at the pn-junction was strongly quenched. Cathodoluminescence measurements confirmed the findings of the photoluminescence measurements.