tailieunhanh - Báo cáo hóa học: " Superlattices: problems and new opportunities, nanosolids Raphael Tsu"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Superlattices: problems and new opportunities, nanosolids Raphael Tsu | Tsu Nanoscale Research Letters 2011 6 127 http content 6 1 127 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Superlattices problems and new opportunities nanosolids Raphael Tsu Abstract Superlattices were introduced 40 years ago as man-made solids to enrich the class of materials for electronic and optoelectronic applications. The field metamorphosed to quantum wells and quantum dots with ever decreasing dimensions dictated by the technological advancements in nanometer regime. In recent years the field has gone beyond semiconductors to metals and organic solids. Superlattice is simply a way of forming a uniform continuum for whatever purpose at hand. There are problems with doping defect-induced random switching and I O involving quantum dots. However new opportunities in component-based nanostructures may lead the field of endeavor to new heights. The all important translational symmetry of solids is relaxed and local symmetry is needed in nanosolids. Introduction Of all the thousands of minerals as jewelry only a few are suitable for electronic devices. Silicon in more than 95 of all electronic devices GaAs-based III-V semiconductors in the rest of the optical and optoelectronic devices and less than 1 used in all the rest such as lasers capacitors transducers magnetic disks and switching devices in DVD and CD disks comprise a very limited lists of elements. For this reason Esaki and Tsu 1 2 introduced the concept of man-made superlattices to enrich the list of semiconductors useful for electronic devices. In essence superlattice is nothing more than a way to assemble two different materials stacked into a periodic array for the purpose of mimicking a continuum similar to the assemble of atoms and molecules into solids by nature. Although it was a very important idea the technical world simply would not support such activity without showing some unique features 3 . We found it in the NDC negative .