Epitaxial Non c-Axis Twin-Free Bi2Sr2CaCu2O8+δ Thin Films for Future THz Devices

Abstract

Thin films of (117) Bi2Sr2Ca2CuO8+δ (Bi-2212) were grown by Molecular Organic Chemical Vapor Deposition (MOCVD) on (110) SrTiO3 and (110) LaAlO3 substrates. Substrates were vicinal with off angles up to 20°. Films are 3D epitaxial and X-ray diffraction φ-ψ scans demonstrate that, while the films grown on a flat substrate are composed of twinned grains, the films on vicinal substrate are twin-free. A higher quality is obtained if growth is performed at two temperatures: Growth starts at 550–600 °C and continues at 700–750 °C. The twin-free film grown by the two-temperature method shows a zero-resistance critical temperature of 37 and 32 K when the measuring current is applied in-plane parallel and perpendicular to [001] direction of the substrate. Twin-free non c-axis thin films are promising for fabrication of novel planar THz devices.

Special Issue “Advances in Epitaxial Materials”-Editorial Preface

“…In the Special Issue, four papers [1,3,4,10] report epitaxial growth using Metalorganic Chemical Vapor Phase Epitaxy (MOVPE). This is the most popular method used for growing most epitaxial layers in the semiconductor industry.…”

“…In industry, MOVPE is likely to dominate by more than one order of magnitude. Two other papers used Liquid Phase Epitaxy [8] and magnetron sputtering [10]. Both techniques are much cheaper than MOVPE and MBE, and may find, in future, some niche applications.…”

“…As THz devices are very desirable in many applications, such as cancer diagnosis, food inspection, explosive detection, electronics, and communications, there are many groups working in that field. In this Special Issue, Kazuhiro Endo et al [10] report on the growth and properties of BiSrCeCuO layers on SrTiO 3 and LaAlO 3, which are promising materials for THz devices.…”

Phase purity and surface morphology of high-J superconducting Bi2Sr2Ca1Cu2O8+δ thin films

“…Thin film applications exploiting the quasi-2D transport properties of HTS materials require epitaxial layers that are grown on lattice matched substrates or buffer layers. HTS thin films of well-defined unit cell lattice orientation offer several device applications, for instance, as THz radiation emitters [1][2][3][4]. Such films are also ideal materials to study the properties of the magnetic flux quanta (vortices) and vortex lattices.…”