11.1 INTRODUCTION

Most of the key components for information technology are based on semiconductor devices with electronic or optoelectronic functions [1]. From a physical point of view almost all those devices rely on 3D- or 2D-semiconductor systems which are operated in an incoherent regime. Within the last 20 years, the field of basic semiconductor research has moved more and more towards nanostructures. One of the major driving forces in this evolution was certainly the general trend to go towards smaller and smaller devices, which have been predicted to give enhanced performance [2]. Another even more fundamental aspect was connected with the new ability to resolve individual quantum states in a solid [3 8]. This in turn can lead in the future to new classes of devices that offer quantum controlled functions [9]. Today high quality QDs are available to the community, which are regarded to be key elements in future solid state electronics and optoelectronics. In the field of optical spectroscopy, single quantum dots have now been studied very intensively, covering single and many body aspects, as well as electron-phonon interactions, dynamics, coherent properties, and more (see [10] and references therein).

The focus of this chapter is on quantum dot diodes. The purpose of the work presented in the following sections is to explore functionalized quantum dot systems in view of both basic physics and future applications. Common to all sections is that quantum dots have been introduced in electric field tunable diode structures. With...