Epitaxial rhenium buffer layers on Al2O3(0001): a substrate for the deposition of (111)-oriented heteroepitaxial diamond films

Abstract

Thin rhenium buffer layers deposited on c-sapphire surfaces were studied as potential substrates for the heteroepitaxial deposition of (111)-oriented diamond films. The Re layers were prepared by e-beam evaporation. They formed very flat epitaxial films with mosaicity values below 0:2 o . Application of the bias enhanced nucleation (BEN) procedure caused a characteristic roughening of the rhenium surface. The dimensions of the occurring surface structures were similar to those found on iridium (001). After the BEN procedure, a huge carbon supersaturation of 7.2% within the rhenium layer was measured. It was accompanied by a pronounced volume expansion of the Re unit cell, which could be reversed by a hydrogen plasma treatment. (111)-oriented epitaxial diamond was formed with two equivalent orientations due to the sixfold symmetry of the Re(0001) surface. The full width at half maximum for tilt and twist, 4:8 o and 3:0 o respectively, is significantly lower than for similar (111)-oriented diamond films on silicon. This qualifies epitaxial Re layers as promising substrates for the deposition of (111)-oriented epitaxial diamond films.

Induced Superconductivity in Graphene Grown on Rhenium

“…Indeed, while the classical transport experiments are dependent on the transparency T of the interface, the proximity effect ruled by the Andreev reflection is T 2 dependent. In this work we demonstrate a new efficient way to induce superconductivity into graphene by directly growing it onto rhenium, taking advantage of both its catalytic and superconducting properties.Epitaxial Re thin films with 30 nm thickness were grown using electron beam evaporation in a molecular beam epitaxy setup onto polished single-crystal α-Al 2 O 3 (0001) wafers which were previously cleaned by annealing under ultrahigh vacuum for 5 h at 573 K [12]. The Re deposit was conducted at 773 K at a rate of 8Å/min.…”

Prospects for the synthesis of large single-crystal diamonds

“…The oriented and heteroepitaxial diamond growth is exemplified by such different materials as sapphire [69], Co [70], Pt [71], TiC [72], graphite [73], BeO [74], Ni 3 Ge [75], and Re [76], which are not discussed below. Detailed reviews of the synthesis of heteroepitaxial and textured diamond films can be found in monographs [2,6,49].…”

Epitaxy of Carbon-Based Materials

“…Heteroepitaxy diamond has been demonstrated on various substrates such as c-BN [76], Pd [77], Ni [78], graphite [79], Pt [80], Re [81], Si [82], and Ir [83][84][85][86][87][88][89][90][91][92]. Thus far, it is experimentally and theoretically accepted that Ir is an exceptional substrate to achieve heteroepitaxial diamond films rather than others.…”