English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Within this work, the “metal assisted chemical etching” (MACE) technique was combined with shadow nanosphere lithography to fabricate nanowire structured Si surfaces with different wire lengths and diameters. Electropolishing procedures subsequent to the wire growth resulted in a reduction of the surface defect density (DSS), which is generally increased after texturization processes such as MACE. With the help of in situ photoluminescence spectroscopy, it was possible to directly monitor the surface properties during the electropolishing experiments. Previous works already observed a full and air stable surface passivation of flat Si surfaces by methylation. Also in the present work, the nanowire surfaces were methylated after the electropolishing procedure to preserve the reduced DSS. To determine the impact of this method on the solar cell performance, the electropolished and methylated surfaces were combined with the conductive polymer PEDOT:PSS. The solar cell parameters of the fabricated hybrid solar cells were then compared with the parameters of the cells that did not contain electropolished substrates. It revealed that the cells with the electropolished substrates exhibit a higher efficiency and an increased short circuit current (JSC). Three different electrochemical procedures to change the wire morphology after the structuring, like potential scans, potential sweeps and the application of a constant potential, have been investigated as well. The methyl passivation is primarily implemented to prevent the surface from oxidation. However, to use the Si substrates for other applications, such as biosensing, different passivation/functionalization techniques are required. In this thesis, a new functionalization procedure was developed to obtain air stable hydroxyl groups that are directly bound to the Si substrate without an intervening oxide layer. Usually, hydroxyl groups are only present on the Si oxide layer due to the fast oxidation of Si at ambient conditions. To demonstrate the possibility to use these hydroxyl groups in the same way as the hydroxyl groups present on a Si oxide layer, further modifications with different silane species, such as APTES and AMMS, were conducted. In case of APTES, the terminal amino groups already enable the immobilization of biomolecules. In order to generate a more selective anchor group, the bound APTES molecules were further modified by a maleimide derivative, which allow for the selective binding of thiol-containing molecules.

Synthesis, tailoring and passivation of Si nanowires towards hybrid devices