Are you an EPFL student looking for a semester project?
Work with us on data science and visualisation projects, and deploy your project as an app on top of GraphSearch.
Selective area epitaxy constitutes a mainstream method to obtain reproducible nanomaterials. As a counterpart, self-assembly allows their growth without costly substrate preparation, with the drawback of uncontrolled positioning. We propose a mixed approach in which self-assembly is limited to reduced regions on a patterned silicon substrate. While nanowires grow with a wide distribution of diameters, we note a mostly binary occurrence of crystal phases. Self-catalyzed GaAs nanowires form in either a wurtzite or zincblende phase in the same growth run. Quite surprisingly, thicker nanowires are wurtzite and thinner nanowires are zincblende, while the common view predicts the reverse trend. We relate this phenomenon to the influx of Ga adatoms by surface diffusion, which results in different contact angles of Ga droplets. We demonstrate the wurtzite phase of thick GaAs NWs up to 200 nm in diameter in the Au-free approach, which has not been achieved so far to our knowledge.
Loading
Loading
Loading
Loading
Loading
Nicolas Bologna, Rolf Erni, Anna Fontcuberta i Morral, Luca Francaviglia, Kirsten Emilie Moselund, Heike Riel
Sonia Conesa Boj, Anna Dalmau Mallorquí, Anna Fontcuberta i Morral, Federico Matteini, Heidi Andrea Potts, Eleonora Russo, Jelena Vukajlovic Plestina
Sonia Conesa Boj, Anna Fontcuberta i Morral, Martin Heiss, Efthimios Kaxiras, Jun Ren, Emanuele Uccelli