High Pressure Semiconductor Physics

Abstract

The present issue of physica status solidi (b) contains a Special Section of papers (Three Invited Articles and 18 Original Papers) that are based on contributions presented at the 15th High Pressure Semiconductor Physics (HPSP15) International Conference held in Montpellier, France, from July 25th to 27th, 2012. This conference was the fifteenth in a series of biennial meetings held under the general title “International Conference on High Pressure Semiconductor Physics” organized as a satellite of the International Conference on the Physics of Semiconductors (ICPS). During the past thirty years, the HPSP series of conferences has been established as a leading event for the scientific community involved in the application of high pressure and other forms of high stress in the study of semiconductors and their micro/nano-structures. The contents of HPSP evolves together with the scientific challenges associated with the technological uses of semiconductor materials and systems, as well as with the evolution of the technical tools and methods – both experimental and theoretical – utilized in fundamental and applied investigations. In particular, the emergence of novel nano-materials and nano-systems has been an important development in the last twenty years, such that semiconductors at the nanoscale constitute now an important topic of HPSP. On the other hand, the more “traditional” semiconductor systems have to face new challenges due to their progressive miniaturization in microelectronics or to their new technological application which results from the demands of the society in the 21st century. All this calls for a better fundamental understanding of the physics of semiconductors through efficient predictive tools, precise experimental work and novel synthesis processes. Several years ago, the organizers of the conference series made an effort to widen the scope of HPSP by not applying a narrow definition of semiconductor physics, but including new materials and novel experimental approaches. Within the case materials of the HPSP15 conference one can still find group-III nitrides and the discussion of remaining open questions concerning their electronic, vibrational as well as optical properties 1, but also carbon based nanomaterials such as fullerenes, carbon nanotubes and, very recently, graphene, or a new class of materials that behave as insulators in the bulk but conduct electrical current in the surface, so-called topological insulators 2. Probing semiconductors at highly anisotropic strains is difficult due to the inherent limitations of the commonly used static compression methods to generate the hydrostatic pressure or uniaxial stress. The uniaxial strain conditions produced during strong dynamic compression can overcome these limitations and have revealed lately important electronic structure changes 3. From the more technological point of view several papers deal with investigations of laser diodes under high pressure. They arrive not only at a better understanding of the lasing mechanisms at work but also at practical applications, for instance, allowing for the pressure tuning of lasers in the 1 to 1.5 micrometer range 4.