In recent years, with the advent of fine line lithographical methods,
molecular beam epitaxy, organometallic vapour phase epitaxy and other
experimental techniques, low dimensional structures having quantum
confinement in one, two and three dimensions (such as ultrathin films,
inversion layers, accumulation layers, quantum well superlattices,
quantum well wires, quantum wires superlattices, magneto-size
quantizations, and quantum dots) have attracted much attention not only
for their potential in uncovering new phenomena in nanoscience and
technology, but also for their interesting applications in the areas of
quantum effect devices. In ultrathin films, the restriction of the
motion of the carriers in the direction normal to the film leads to the
quantum size effect and such systems find extensive applications in
quantum well lasers, field effect transistors, high speed digital
networks and also in other quantum effect devices. In quantum well
wires, the carriers are quantized in two transverse directions and only
one-dimensional motion of the carriers is allowed.
The available books on semiconductor science and technology cannot
afford to devote even an entire chapter to photoemissions from
optoelectronic materials, although its importance in photoemission
spectroscopy is extremely well known. This book deals totally with the
photoemission from optoelectronic materials and their nanostructures
(ultrathin films, quantum wires, superlattices, etc.).