Short-Period CdO/MgO Superlattices as Cubic CdMgO Quasi-Alloys

Ewa Przezdziecka,Aleksandra Wierzbicka,Piotr Sybilski,Piotr Dłuzewski,Iwona Sankowska,Krzysztof Morawiec,Adrian Kozanecki,Mirosław A Pietrzyk

doi:10.1021/acs.cgd.0c00678

Abstract

New perspective cubic quasi-alloy {CdO/MgO}m short-period superlattices (SLs) were grown on r-plane sapphire substrates by plasma-assisted molecular beam epitaxy. The quality of crystals was charac...

Highlights

Pure CdO is a promising transparent conducting oxide (TCO) which exhibits metal-like charge transport behavior with an exceptionally large carrier mobility.[1]
Topography of samples was analyzed with a Vecco Icon Atomic Force Microscopy system (AFM) tapping mode, and crystal structure was determined using a Titan Cubed 80−300 transmission electron microscope operating at 300 kV in high-resolution (HRTEM) and scanning high-angle annular dark field (STEM/HAADF) mode experiments
The samples were grown at a relatively low temperature (360 °C on the thermocouple), their good crystal quality has been obtained as demonstrated by the X-ray diffraction (XRD)

Summary

INTRODUCTION

Pure CdO is a promising transparent conducting oxide (TCO) which exhibits metal-like charge transport behavior with an exceptionally large carrier mobility.[1]. To overcome difficulties related to phase separation and spontaneous formation of nanocrystals, an approach consisting of the use of short period {CdO/MgO}m superlattices (SLs) is proposed in this work. In such SLs, the layer thicknesses are on the order of few atomic layers only. It is a novel type of SL which can be used to obtain high-quality TCO layers We show that such approach can solve the problem of phase separation in spite of intrinsic difficulties in fabricating such structures related to the different growth conditions for the two binary CdO and MgO compounds. We decided to grow the structures at the same temperature of 360 °C, in agreement with the results by Zuniga-Perez that growth temperature near 380 °C is favorable for growing good quality CdO layers on r-Al2O3 by metalorganic vapor phase epitaxy (MOVPE).[24]

EXPERIMENTAL SECTION

RESULTS AND DISCUSSION

CONCLUSIONS

■ REFERENCES