Monolithic integration of transition metal oxide multiple quantum wells on silicon (001)

• Published in: Journal of applied physics Vol. 125; no. 15
• Main Authors: Ortmann, J. Elliott, Kwon, Sunah, Posadas, Agham B., Kim, Moon J., Demkov, Alexander A.
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 21.04.2019
• Subjects: Applied physics; Conduction bands; Coordination compounds; Current carriers; Electron diffraction; Electron gas; Heterostructures; Insulators; Light sources; Metal oxides; Molecular beam epitaxy; Optical properties; Photonics; Quantum phenomena; Quantum wells; Silicon; Strontium titanates; Transition metal oxides; Transition metals; X-ray diffraction
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.5086874

The SrTiO3/LaAlO3 (STO/LAO) system has been the subject of intense research efforts since the discovery of a two-dimensional electron gas at the interface of these two band insulators. However, recent reports have focused on the system's optical properties arising from the huge 2.4 eV conduction band offset between STO and LAO and the ability to confine charge carriers in STO quantum wells. While the STO/LAO system shows promise for use in a variety of next-generation optical and electro-optical devices, the technological compatibility of such devices relies in large part on the successful integration of high-quality STO/LAO quantum structures on silicon. In this report, we demonstrate the monolithic integration of STO/LAO multiple quantum wells on silicon (001) with molecular beam epitaxy. Our electron diffraction, X-ray diffraction, and electron microscopy results indicate the excellent crystalline quality with which these heterostructures can be fabricated. We consider the correlated strain and thermal mechanisms at play in our heterostructures and how they contribute to heterostructure growth. Furthermore, we discuss general considerations for the deposition of other complex transition metal oxide heterostructures on silicon. Our results support the potential for STO/LAO quantum structures to find use in next-generation optical devices, including integrated sensors, light sources, and photonics.