Regensburg 2013 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 70: Poster Session: Devices; Preparation and characterization; C/diamond; Si/Ge
HL 70.6: Poster
Mittwoch, 13. März 2013, 16:00–20:00, Poster A
Narrow bandwidth ultraviolet photodetectors based on wide band gap semiconductors — •Zhipeng Zhang, Friedrich-Leonhard Schein, Holger von Wenckstern, and Marius Grundmann — Universität Leipzig, Fakultät für Physik und Geowissenschaften, Institut für Experimentelle Physik II, Linnéstraße 5, 04103, Leipzig
The integration of an optical filter layer allows fabrication of wavelength-selective, visible-blind ultraviolet photodetectors (PDs) based on (Mg,Zn)O-heterostructure being only sensitive in a defined, narrow spectral range [1]. Up to now, this was accomplished by growing the active layer of a backside detector on top of a buffer layer having a slightly higher band gap. In this contribution we demonstrate the potential of a novel device layout allowing to achieve much narrower bandwidth by the decoupling of the optical filter and the active layer. Within this approach interdiffusion between the layers is avoided and carriers generated in the filter layer will not contribute to the photocurrent. The achieved bandwidth of this kind at 3.4 eV was 12 meV smaller than that of the previous design.
Furthermore, the properties of a p-ZnCo2O4/n-ZnO heterojunction [2] under illumination were investigated. This bipolar diode can be used as PD similar to the PDs described above. Additionally, such pn-junction can be used as visible-blind solar cells. A first wavelength selective PD with a bandwidth of 60 meV was realized.
[1]: Z. Zhang et al., Appl. Phys. Lett. 99, 083502 (2011)
[2]: F-L. Schein et al., IEEE Electron Device Lett. 33, 676 (2012)