Coulomb-blockierter Elektronentransport über einzelne vergrabene InAs-Quantenprodukte in AIGaAs/GaAs-Heterostrukturen

Product Description

In the new millennium, as a customer in a computer specialty store, one can buy a personal computer, for example with a Pentium III microprocessor with a clock frequency of 600 MHz with 128MB RAM memory. The minimum structure size in the case of the processor lies at a width of isolating lines of 170 nm. However, as the past years show, this "record" is only of short duration, because soon the next generation of processors will be on the market, whose development and testing phase has already been completed. In this ongoing process of the "top-down" strategy, that is, the ever-progressing miniaturization of structures, one constantly encounters technical, occasionally even physical limits with the common production and development methods, which repeatedly force manufacturers to develop new or modified processes. However, the physical limit for the functionality of transistors has not yet been reached; it is predicted for the end of the next decade. From then on, other concepts must be realized to produce more efficient components. A Single-electron transistor, which is already well-known to fundamental research, would represent the smallest electronic memory, since only a single electron is needed for a switching state, for an information bit, whose function could already be demonstrated at room temperature. To realize these ultimate electrical switches, there is the "bottom-up" strategy alongside the "top-down" approach, in which a specific number of atoms or molecules are combined into clusters with the help of self-organizing mechanisms. An example of such clusters are semiconductor quantum dots, which, in contrast to lithographic techniques, arise through self-ordering processes. In the past, they have been intensively characterized optically. Their electrical transport properties are determined by quantum and Coulomb blockade effects.