Authors: T. Tätte, V. Jacobsen, M. Paalo, R. Branscheid, M. Kreiter, U. Mäeorg, K. Saal, A. Lõhmus and I. Kink
Affilation: Tartu University, Estonia
Pages: 305 - 308
Keywords: sol-gel, SPM tips, optical fibres, STM, luminessence
Development of various kinds of sharp needles has been in focus of investigators since their application as sensors in scanning probe microscopy. Although transparent and conductive tips lead to several fascinating applications like STM/SNOM hybrid microscopy, they have received less attention mainly because of difficulties in preparing such tips. Recently as a potential breakthrough in this field we propose a new method based on pulling of Sb doped SnO2 tips from the mixture of stannoxanes . In this work we will further demonstrate suitability of the probes for applications. We measured several critical parameters such as tip radii ~50nm; transparency up from 400 nm and conductivity approximately 2_. We proved that stable STM image with atomic vertical and nanometre lateral resolution is possible with the tips. Also, applied voltage over 7-8 volts caused emission of photons generated by tunneling current resulting in photon maps of the scanned area. We present new results on optimizing tips preparing process. The influence of pulling speed, humidity and viscosity on the tip radius and angle were measured. Finally we will propose a method for making large tip arrays instead of single tips.  T. Tätte et.al. Material Science and Enginering C 19 (2002) 101-104.