Ultrasensitive Current Sensor with Quantum Dots

Quantum dots, quasi zero dimensional systems, can be produced via lithographic procedures or via chemical processes. If quantum dots are connected to electrical leads by tunnelling barriers single electron tunnelling can be observed. Such devices are called single-electron transistors. Since few years it is possible to detect the tunnelling of the individual electrons at low temperatures in a time-resolved fashion with a nearby quantum point contact. In this way the electrons can be counted and the electrical current flowing through the quantum dot is measured. This technique allows for detection of smallest currents. Measurements of few attoamperes are routinely achieved. In decreasing the size of the quantum dots room temperature operation of these ultrasensitive current sensors is possible.

Within this project such sensors will be produced and studied in detail. A decrease of the size of the quantum dots can be achieved via lithographic procedures but also in using chemical methods. In this way the sensors will be developed further to allow for room temperature operation. Different material systems, as e.g. graphene, but also e.g. CdSe/CdS systems will be used. The applicability of these sensors in different environments will be tested.