Berlin 2024 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 44: Nitrides: Preparation and characterization II

HL 44.3: Talk

Thursday, March 21, 2024, 14:30–14:45, EW 015

uniform large-area top-down GaN nanowire array fabrication with independently tunable diameter and spacing — •jingxuan kang, rose-mary jose, thomas auzelle, oliver brandt, and lutz geelhaar — Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Berlin, Germany

Top-down approaches to nanowire fabrication offer advantages in controllability over bottom-up growth. However, achieving large-area nanoscale patterning with high throughput poses challenges. This study explores the use of nanoislands resulting from the dewetting of a metal film as mask for GaN nanowire fabrication. To optimize size and shape homogeneity, we have extensively varied the annealing conditions for Pt films of different thicknesses. A thermodynamic model accurately describes the experimental dependencies of island diameter and density on film thickness, as well as the linear relation between island spacing and diameter.

To overcome the fixed spacing-diameter relation imposed by dewetting, we employ digital etching of the GaN nanowires fabricated with the above islands. O₂ plasma oxidation followed by KOH wet etching enables a precise reduction of the nanowire diameter, increasing at the same time the spacing. Hence, additional freedom is gained for tailoring the nanowire array properties. Combining metal dewetting with controlled lateral nanowire etching offers a pathway for large-scale top-down nanowire fabrication with both high throughput and flexibility in dimension control.

Keywords: nanowire; GaN; dimension controlling; top-down fabrication