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DS: Fachverband Dünne Schichten
DS 17: Poster Session I
DS 17.14: Poster
Tuesday, March 13, 2018, 18:15–20:15, Poster B
Occurence of the є-phase in (InxGa1−x)2O3 and (GaxAl1−x)2O3 thin films — •A. Werner1, H. von Wenckstern1, C. Sturm1, D. Splith1, V. Prozheeva2, R. Hoelldobler1, and M. Grundmann1 — 1Halbleiterphysik, Universität Leipzig, Leipzig, Germany — 2Department of Applied Physics, Aalto University, Espoo, Finland
The wide bandgap semiconductor Ga2O3 appears in five polymorphs of which only the so-called є-phase has a high spontaneous polarization P along its c-axis[1].
Within heterostructures, a discontinuous change of P at the heterointerface occurs, resulting in charge accumulation. Therefore, stabilization of the є-phase within the ternary alloys (In,Ga)2O3 or (Ga,Al)2O3 is required in order to utilize the two-dimensional charge carrier gases within electronic devices.
We present studies of the occurrence of the є-phase in ternary alloys of Ga2O3 with In2O3 and Al2O3. Samples with continuous composition spread[2] were grown by pulsed laser deposition on (00.1) Al2O3.
As target segments we used Ga2O3/In2O3 or Ga2O3/Al2O3.
Each segment was additionally doped with tin to facilitate the formation of the є-phase[3].
Resulting thin films were investigated by means of X-ray diffraction, transmission, energy-dispersive X-ray spectroscopy, Raman spectroscopy, and atomic force microscopy.
We observed a monotonic shift of the є-reflexion in dependency of In-/Al-content; for example the (002)-reflex shifts to lower angles with increasing In-content.
[1] M. B. Maccioni et al., Appl. Phys. Express 9, 04102 (2016).
[2] H. v. Wenckstern et al., CrystEngComm 15, 10020 (2013).
[3] M. Kracht et al., Phys. Rev. Applied 8, 054002 (2017).