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HL: Fachverband Halbleiterphysik

HL 68: Poster Session: GaN: devices & preparation & characterization; III-V semiconductors; Photonic crystals; Semiconductor lasers

HL 68.1: Poster

Mittwoch, 13. März 2013, 16:00–20:00, Poster A

Characteristics of AlGaN Schottky photodiodes for UV-C detection — •Simon Kapanke¹, Jessica Schlegel¹, Andrea Knigge², Xuemei Wang³, Jens Rass¹, Hassan Gargouri³, Frank Brunner², Markus Weyers², and Michael Kneissl^1,2 — ¹Technische Universität Berlin, Institut für Festkörperphysik, Hardenbergstr. 36, 10623 Berlin — ²Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Str. 4, 12489 Berlin — ³SENTECH Instruments GmbH, Schwarzschildstr. 2, 12489 Berlin

We have investigated the influence of absorption layer doping on the photoresponse characteristics of solarblind AlGaN Schottky photodiodes by photocurrent spectroscopy, I-V measurements and device simulations. The responsivity maximum of photodiodes with moderate Si-doping of the Al_0.45GaN absorption layer shifts to shorter wavelengths compared to devices with non-intentionally doped absorption layer due to a decreased widths of the space charge region. Additionally, the responsivity can be enhanced by increasing the UV-C transmission of the semi-transparent Schottky contact. Photodetectors with SiO₂ or Al₂O₃ anti-reflection coating showed UV-C responsivities of up to 90 mA/W. The SiO₂ coatings were deposited using a Sentech inductively coupled plasma enhanced chemical vapor deposition (ICPECVD) system SI 500 D and for Al₂O₃ a Sentech atomic layer deposition (ALD) system SI ALD LL was applied. The influence on the spectral and electrical device characteristics of coatings deposited by these techniques in comparison to sputtered SiO₂ will be discussed.