Properties of Thin Film-Covered GaN(0001) Surfaces

Gallium nitride (GaN), a wide band gap semiconductor (E_g=3.4 eV) has unique physical properties which opened up the door to widespread applications in modern electronic devices. The semiconductor is used as a base for fabrication of visible and UV lasers, light-emitting diodes, high temperature and frequency detectors, and transistors. In all these devices the electronic properties of bare and thin-covered GaN surfaces have impacts on their efficiencies.

Herein surface sensitive techniques with an emphasis on ultraviolet and X-ray photoelectron spectroscopies (UPS and XPS) are used to understand physical and chemical properties of bare and film-covered GaN(0001) surfaces. Thin films of several elements: nickel, palladium, manganese, arsenic and antimony (Ni, Pd, Mn, As, Sb) are included. The properties of bare GaN surfaces [1] as well as various adsorbate/GaN phase boundary are reported [2-7]. Different types of thin films behavior under an influence of annealing in ultrahigh vacuum conditions are distinguish. Metal films form surface alloys with gallium (NiGa, PdGa) while semi-metals layers easy evaporate from GaN surface, however, the layer in direct contact with the substrate can react with it causing a change in the surface properties of GaN(0001).

[1] M. Grodzicki, P. Mazur, A. Ciszewski, Appl. Surf. Sci. 440, 547 (2018)
[2] M. Grodzicki, P. Mazur, et al., Appl. Phys. A 120, 1443 (2015)
[3] M. Grodzicki, P. Mazur, et al., Appl. Surf. Sci. 304, 24 (2014)
[4] M. Grodzicki, P. Mazur, J. Brona, A. Ciszewski, Appl. Surf. Sci. 481, 790 (2019)
[5] M. Grodzicki, P. Mazur, A. Sabik, Sur. Sci. 689, 121460 (2019)
[6] M. Grodzicki, J. Rousset, et al., Appl. Surf. Sci. 493, 384 (2019)
[7] M. Grodzicki, P. Mazur, A. Sabik, Appl. Surf. Sci. 512, 145643, (2020)