NT-MDT Solver Next - Stm Spectroscopies; Current Imaging Tunneling Spectroscopy I(V)

Chapter 7. Performing Measurements
159
7.6. STM Spectroscopies
Before performing the STM spectroscopy it is necessary to perform preliminary
STM measurements of the investigated area topography (see i. 7.4 “Scanning Tunneling
Microscopy” on p. 125).
The preparatory and measurement procedures are similar to those discussed in
i. 7.5.1 ”Force-distance Spectroscopy” on p. 141. Hence, just a brief algorithm is given
below. Only the stages that differ from the standard procedure are considered in detail.
7.6.1. Current Imaging Tunneling Spectroscopy I(V)
The procedure of Current Imaging Tunneling Spectroscopy (CITS) consists in acquisition
of volt-ampere characteristics (VAC) of a tip – sample tunneling junction. VACs provide
information on local conductivity of the sample. Besides, this experimental technique is
useful in studying hetergogeneities of electrical properties in samples of complex
composition.
To making measurements, perform the following steps:
1. Verify that the controller is configured for STM measurements (Fig. 7-141).
Fig. 7-148. Selecting the controller configuration
2. Open the spectroscopy window by clicking the button.
Fig. 7-149. Spectroscopy window
3. In the Spectroscopy Mode drop-down list, select I(V) STM. This will result in:
● selecting the IProbe signal as a recorded signal in the Measurements panel;
● selecting the BV Value as the argument of the measured relation in the Argument
panel.
Redefine the set of measured signals, if necessary.