Regensburg 2016 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 53: Poster II

HL 53.6: Poster

Mittwoch, 9. März 2016, 09:30–13:30, Poster A

Electrical transport in γ-CuI crystals and thin films and usage in bipolar γ-CuI/ZnO-heterodiodes with high rectification ratio — •Max Kneiß, Chang Yang, José Barzola-Quiquia, Michael Lorenz, and Marius Grundmann — Universität Leipzig, Institut für Exp. Physik II, Germany

The interest in γ-CuI has increased recently, as it is an intrinsically p-conducting transparent semiconductor with a high excitonic binding energy of 62 meV and fairly high hole mobility making it a promising alternative for usage in transparent optoelectronics [1]. We investigated γ-CuI crystals and thin films grown with various techniques via temperature dependent Hall-Effect-, I-V- and magnetoresistance measurements. We modeled the temperature dependent resistance and I-V-curves and found evidence for a tunneling process dominating the transport at low temperature in both crystals and thin films. A change from semiconducting to metallic behaviour with increasing temperature is observable only for thin films, where a power law is characterizing the resistance at higher temperature, which is in agreement with the high carrier concentrations in our thin films (≈ 10¹⁹-10²⁰ cm⁻³). Magnetoresistance furthermore suggests a weak antilocalization effect for crystals at low temperatures. Finally we were able to grow CuI thin films epitaxially on a ZnO-layer via reactive sputtering thus producing transparent γ-CuI/ZnO-heterodiodes with even higher rectification ratios (up to 9 orders of magnitude) than previously reported [2].

[1] Grundmann et al., Phys. Status Solidi A 210, 1671 (2013)

[2] Schein et al., Appl. Phys. Lett. 102, 092109 (2013)