We have also installed an Omicron UHV scanning probe microscope (SPM) (Figure 1) that allows characterisations in a temperature range between 30 and 650 K. The UHV SPM system combines the functionalities of a scanning tunnelling microscope (STM) and an atomic force microscope (AFM) and consists of a flexible two-level preparation chamber. It is designed for high-resolution scanning probe microscopy and additional sample preparation by means of sputtering, heating, or coating of the tips by thin film evaporation. The AFM can be operated in contact modes as well as in noncontact modes. The contact modes allow measurements of the normal and lateral force, force–distance curves, conductive AFM, and piezo response AFM. The corresponding noncontact modes include electrostatic force microscopy (EFM), magnetic force microscopy (MFM), Kelvin probe force microscopy (KPFM), and multimode operation and spectroscopy. By using this equipment, the growth of individual layers can be studied without breaking the vacuum. The process parameters of buffer layers can be optimised to provide a smooth base for further layers to form heterostructures and devices. The scanning tunnelling spectroscopy gives additional information about the surface termination of the films. 

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