TY - CHAP A1 - Ławrowski, Robert Damian A1 - Langer, Christoph A1 - Prommesberger, Christian A1 - Schreiner, Rupert A1 - Mingels, Stephan A1 - Porshyn, Vitali A1 - Serbun, Pavel A1 - Müller, Günter T1 - Field emission from surface textured GaN with buried double-heterostructures T2 - 2015 28th International Vacuum Nanoelectronics Conference (IVNC), 13-17 July 2015, Guangzhou, China N2 - In this contribution we report on field emission (FE) cathodes based on thin-film LED-technology and surface texturing. The FE cathode can be used both as an n-GaN cathode with an electrical contact at the top side metallization as well as a pn-GaN diode contacting only the p-GaN layer at the bottom side of the structure. The local and integral FE properties of the textured surface of the LED structure were investigated. For n-GaN an integral emission current up to 1.0 μA at an electric field of 19 V/μm was achieved. The pn-GaN diode measurements showed an integral current saturation behavior with two orders of magnitude lower FE currents. Regulated voltage scans obtained by FE scanning microscopy revealed a well-distributed emission over the whole cathode area. Measurements under pulsed tunable laser illumination and moderate electric fields indicated charge carrier generation in the buried double-heterostructures at photon energies below 3.5 eV besides normal photoemission above 4.1 eV. KW - CATHODES KW - Current measurement KW - Electric fields KW - field emission KW - Gallium nitride KW - GaN KW - Iron KW - Light emitting diodes KW - photoemission KW - Surface texture Y1 - 2015 U6 - https://doi.org/10.1109/IVNC.2015.7225548 SP - 106 EP - 107 PB - IEEE ER - TY - CHAP A1 - Mingels, Stephan A1 - Porshyn, Vitali A1 - Serbun, Pavel A1 - Lützenkirchen-Hecht, Dirk A1 - Müller, Günter A1 - Prommesberger, Christian A1 - Langer, Christoph A1 - Schreiner, Rupert A1 - Lutzenkirchen-Hecht, Dirk T1 - Photo-enhanced field emission properties of p-doped black Si arrays T2 - 2016 29th International Vacuum Nanoelectronics Conference (IVNC), 11-15 July 2016, Vancouver, BC, Canada N2 - We have carried out systematic investigations of p-type black Si field emitter arrays under laser illumination. As expected the current-voltage characteristic revealed a strong saturation providing a high photosensitivity, which had a maximum on-off ratio of 43 at a maximum current of 13 μA. The saturation current was stable in the dark as well as under illumination with fluctuations <;0.7%. Results from time-resolved measurements of the photo-sensitivity showed a rather fast response but a long decay time. Electron spectra in the dark and under laser illumination revealed the origin of the emission. KW - black Si KW - Decision support systems KW - photo-enhanced field emission Y1 - 2016 U6 - https://doi.org/10.1109/IVNC.2016.7551447 SP - 1 EP - 2 PB - IEEE ER - TY - CHAP A1 - Schreiner, Rupert A1 - Langer, Christoph A1 - Prommesberger, Christian A1 - Mingels, Stephan A1 - Serbun, Pavel A1 - Müller, Günter T1 - Field emission from surface textured extraction facets of GaN light emitting diodes T2 - 26th International Vacuum Nanoelectronics Conference (IVNC), 8-12 July 2013, Roanoke, VA, USA N2 - We report on the field emission properties of GaN LED surfaces. The textured extraction facet acts both as light scattering layer in order to increase the light extraction efficiency of the LED as well as nanostructured cathode surface for the field emission (FE) of electrons. The LED emits blue light with a peak wavelength of around 450 nm. The FE properties were investigated by a scanning microscope. Integral measurements as well as regulated voltage scans for 1 nA FE current over an area of 400 * 400 µm2were used to investigate both overall and local FE properties. A high number of well-distributed emitters with an average field enhancement factor ß of 85 and stable integral emission currents up to 100 µA at an electric field of   80 V/µm (Øanode= 880 µm) were found. Photo-field-emission spectroscopy (PFES) using a tunable pulsed laser revealed an enhanced photo absorption of the InGaN/GaN quantum well structures near the emission wavelength of the LED (<3.5 eV), whereas at high photon energies (>4.1 eV) photoemission from the GaN surface was observed. KW - Gallium nitride KW - Iron KW - Light emitting diodes KW - Cathodes KW - Surface texture KW - Surface waves KW - Photonics Y1 - 2013 U6 - https://doi.org/10.1109/ivnc.2013.6624721 PB - IEEE ER -