RESUMO
Two-dimensional (2D) molybdenum ditelluride (MoTe2) exhibits an intriguing polymorphic nature, showing stable semiconducting 2H and metallic 1T' phases at room temperature. Polymorphism in MoTe2 presents new opportunities in developing phase-change memory, high- performance transistors, and spintronic devices. However, it also poses challenges in synthesizing homogeneous MoTe2 with a precisely controlled phase. Recently, a new yet simple method using sputtering and 2D solid-phase crystallization (SPC) is proposed for synthesizing high-quality and large-area MoTe2. This study investigates the polymorphism control of MoTe2 synthesis using 2D SPC. The Te/Mo ratio and oxygen content in the as-sputtered films correlate strongly with the final phase and electrical properties of SPC MoTe2. Furthermore, the SPC thermal budget may be exploited for stabilizing a deterministic phase. The comprehensive experiments presented in this work demonstrate the versatile and precise controllability on the MoTe2 phase by using the simple 2D SPC technique.
RESUMO
Computed tomography (CT) is increasingly applied as an aid to clinical decision making in congenital heart disease (CHD) with regard to surgery, interventional catheterizations, and follow-up. It is particularly useful for the assessment of vascular and airway abnormalities. Updated knowledge of CT imaging techniques is mandatory not only for the optimization of image acquisition protocols, but also for the postprocessing reconstruction and interpretation of CT findings. The purpose of this article was to review the clinical indications, techniques, and dose reduction methods for CT imaging in children and adults with CHD. Relevant discussion and illustrations of common forms of CHD evaluated by CT are presented.