title: GeSn-on-Si normal incidence photodetectors with bandwidths more than 40 GHz.
abstract: GeSn (Sn content up to 4.2%) photodiodes with vertical pin structures were grown on thin Ge virtual substrates on Si by a low temperature (160 °C) molecular beam epitaxy. Vertical detectors were fabricated by a double mesa process with mesa radii between 5 µm and 80 µm. The nominal intrinsic absorber contains carrier densities from below 1 · 10(16) cm(-3) to 1 · 10(17) cm(-3) for Ge reference detectors and GeSn detectors with 4.2% Sn, respectively. The photodetectors were investigated with electrical and optoelectrical methods from direct current up to high frequencies (40 GHz). For a laser wavelength of 1550 nm an increasing of the optical responsivities (84 mA/W -218 mA/W) for vertical incidence detectors with thin (300 nm) absorbers as function of the Sn content were found. Most important from an application perspective all detectors had bandwidth above 40 GHz at enough reverse voltage which increased from zero to -5 V within the given Sn range. Increasing carrier densities (up to 1 · 10(17) cm(-3)) with Sn contents caused the depletion of the nominal intrinsic absorber at increasing reverse voltages.
authors: Michael
authors: M
authors: Oehme
authors: Konrad
authors: K
authors: Kostecki
authors: Kaiheng
authors: K
authors: Ye
authors: Stefan
authors: S
authors: Bechler
authors: Kai
authors: K
authors: Ulbricht
authors: Marc
authors: M
authors: Schmid
authors: Mathias
authors: M
authors: Kaschel
authors: Martin
authors: M
authors: Gollhofer
authors: Roman
authors: R
authors: Körner
authors: Wogong
authors: W
authors: Zhang
authors: Erich
authors: E
authors: Kasper
authors: Jörg
authors: J
authors: Schulze
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D005857:Germanium / Q000737:chemistry* / Q000528:radiation effects; D008027:Light; D008422:Materials Testing; D008872:Microwaves; D010783:Photometry / Q000295:instrumentation*; D012666:Semiconductors; D012825:Silicon / Q000737:chemistry* / Q000528:radiation effects; D014001:Tin / Q000737:chemistry* / Q000528:radiation effects
chemical_list: D005857:Germanium; D014001:Tin; D012825:Silicon