Dresden 2014 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 44: ZnO and its relatives: Devices

HL 44.1: Talk

Tuesday, April 1, 2014, 10:45–11:00, POT 151

Energy-selective monolithic multichannel ultraviolet photodiodes based on (Mg,Zn)O thin films — •Zhipeng Zhang, Holger von Wenckstern, Jörg Lenzner, and Marius Grundmann — Universität Leipzig, Fakultät für Physik und Geowissenschaften, Institut für Experimentelle Physik II, Linnéstraße 5, 04103, Leipzig

We report on the fabrication of photodiodes employing Schottky contacts based on ternary (Mg,Zn)O thin films in wurtzite modification [1]. We utilize a new concept for forming a continuous composition spread (CCS) [2] within the active layer allowing the design of energy-selective, monolithic and multichannel ultraviolet metal-semiconductor-metal photodiodes [3]. The CCS of (Mg,Zn)O thin film was realized by pulsed-laser deposition on a 2 inch double-sided polished a-plane sapphire wafer using a single segmented target. The Mg-content and with that the bandgap change linearly along the compositional gradient [2].

The photo response of the photodiodes with a defined spectral bandwidth is enabled by an integrated optical filter layer providing a high energy cutoff. Further, we also have fabricated photodiodes from a wafer with separated active and filter layer with lateral graded CCS. By that the onset of absorption was tuned over 330 meV and the bandwidth of the photodiodes can be controlled from 270 meV down to about 30 meV.

[1]: Z. Zhang et al., Appl. Phys. Lett. 99, 083502 (2011)

[2]: H. von Wenckstern et al., CrystEngComm. 15, 10020 (2013)

[3]: Z. Zhang et al., Appl. Phys. Lett. 103, 171111 (2013)