Correlated discrete transfer of single electrons in ultrasmall tunnel junctions is of great interest for applications in molecular electronics. We report single-electron tunnelling at 300 K in the double tunnel junction system "graphite substrate-carboran cluster-STM tip". The problem of reliably fixing clusters on the graphite surface has been solved by means of cluster incorporation into a stearic acid LB (Langmuir-Blodgett) monolayer matrix. We obtained compression isotherms of mixed monolayers with varying molar ratio [stearic acid]:[clusters]. STM images of deposited mixed films revealed that the clusters formed a regular structure.