Semiconductor-baser quantum dots are ideal for quantum information applications due to their discrete, atom-like density of states and ease of integration into conventional semiconductor devices. In this internship we propose to explore coupled quantum dots, or so-called quantum dot molecules, where two dots are close enough that carriers can tunnel coherently between them. This system has great potential as the quantum gate needed for quantum computation. By controlling the number of charge carriers in the molecule, a spin qubit with a large coherence time can be created, about two orders of magnitude longer than the coherence time of a single spin in a QD. The intern will perform single quantum dot molecule spectroscopy at low temperature under applied external bias in order to characterize the electronic spectrum and identify the spin states that are at stake. The long term goal is to manipulate the quantum states with sequences of optical pulses in order to initialize, control and read the qubits.