Photon Scanning Tunneling Microscope with Outstanding Detection Efficiency and High Time Resolution

Scanning Tunneling Microscopy induced Luminescence (STML) is a powerful technique to record topography and simultaneously spatially resolved photon maps with atomic resolution to localize emission centers. Since the development in the late 1980s, the main challenge of this method is to obtain a reasonable and reproducible photon intensity. In this work, a new STML setup featuring a large parabolic mirror that covers about 75% of the upper hemisphere is presented. It was especially designed for high a detection efficiency and high dynamic range to investigate sensitive molecular emitters below the nanoscale and nanosecond range. A maximum count rate of about 6 million photons per second at 1 nA tunneling current has been measured that result from the decay of plasmon-polariton excitations between an Ag(111) surface and an Ag tip, highlighting the outstanding performance of the setup. The results are exceeding theoretical predictions as well as other experimental setups by about one order of magnitude. With STML experiments, one can study the electronic surface states or molecular orbitals with submolecular resolution e.g. at the HOMO and LUMO levels to study photon excitation processes and energy conversion on a molecular level. With the new STML setup presented in this thesis, polycyclic aromatic hydrocarbons were investigated which are considered good candidates for molecular based single photon sources since they offer high brightness and narrow spectral emission lines. The high demand for single photon sources for applications in quantum cryptography, quantum computing, quantum optics or spectroscopy is reflecting the importance of the field of research. Studies towards molecular based single photon sources based on a C60 matrix and the polycyclic aromatic hydrocarbons DBT and DBATT are presented. Further, the high frequency capability of the scanning tunneling microscope is proven that enables the possibility to electrically drive emitters below the nanosecond range.