Physico-Chemical nanomaterials science

Quantitative analysis of indium deposited layer formation mechanism for In/In4Se3 (100) nanosystem
P.V. Galiy1, P. Mazur2, T.M. Nenchuk1, I.R. Yarovets1, O.R. Dveriy3, I.O. Poplavskyy4
1 Electronics and Computer Technology Department, Ivan Franko Lviv National University, 50 Dragomanov Street, Lviv, 79005, Ukraine.
E-mail: galiy@electronics.lnu.edu.ua
2 Institute of Experimental Physics, University of Wrocław, pl. Maxa Borna 9, 50-204 Wrocław, Poland.
3 Chair of Electromechanics and Electronics, National Academy of Land Forces, 32 Geroiv Majdanu Street, Lviv, 79012, Ukraine
4 Vasyl Stefanyk Precarpatian National University, 57 Shevchenka str., Ivano- Frankivs'k 76025, Ukraine

Quantitative analysis of the formation of indium sub and mono-layer coatings on (100) surface of In4Se3 layered semiconductor crystal was conducted using scanning tunneling spectroscopy (STS) data from Omicron NanoTechnology STM/ AFM System obtained in UHV. To quantify the presence of indium metallic clusters on a semiconductor surface, a simple algorithm for analyzing an array of experimental data was used by determining the frequency of occurrence of tunneling currents above a certain limit value in the range of bias voltages corresponding to 0.67 eV In4Se3 band gap width. There is a clear dependence of the metal points' number of analysis on indium deposition time. At the same time, it is possible to achieve the activation-migration movement of the deposited metallic component over the studied area with its localization at the In activation growth centers, that are naturally present on the initial In4Se3 (100) surface in concentration depending on crystal growth conditions, with formation of 0D and 1D shaped nanostructures.
The STS spectra analyses acquired as spatially integrated over the 50x50 nm2 semiconductor surface areas show good correlation between the time of indium deposition and the reduction of In4Se3 band gap as determined from differential normalized I-V curves, as well as the qualitative transition to the formation of the metallic phase of indium. In the latter case, the appearance of a predominant maximum of surface state density in the vicinity of the Fermi level is achieved, which is typical for the STS of the metal spectra.