Nanooptics and photonics

Fluence dependence of nanosize defect layers in arsenic implanted HgCdTe epitaxial films studied with TEM/HRTEM
I.I. Izhnin1, K.D. Mynbaev2, Z. Swiatek3, J. Morgiel3, A.G. Korotaev4,  
A.V. Voitsekhovskii4, O.I. Fitsych5, V.S. Varavin6, S.A. Dvoretsky4,6, 
N.N. Mikhailov6, M.V. Yakushev6, O.Yu. Bonchyk7, H.V. Savytskyy7
1 Scientific Research Company “Electron-Carat”. Stryjska St., 202, Lviv-79031, Ukraine. E-mail: i.izhnin@carat.electron.ua
2 Ioffe Institute. Politekhnicheskaya St., 26, St. Petersburg-194021, Russia.
3  Institute of Metallurgy and Material Science PAN. Reymonta St., 25, Krakow- 30-059, Poland. 
4 National Research Tomsk State University. Lenina Av., 36, Tomsk-634050, Russia.
5P. Sagaidachny National Army Academy. Gvardijska St. 32, Lviv-79012, Ukraine.
6 A.V. Rzhanov Institute of Semiconductor Physics, SB RAS. ac. Lavrentieva Av., 13,  Novosibirsk-630090, Russia. 
7 Ya.S. Pidstryhach Institute for Applied Problems of Mechanics and Mathematics NASU. Naukova St., 3b, Lviv-79060, Ukraine.
We report on the results of comparative study of fluence dependence of defect layers in molecular-beam epitaxy-grown epitaxial film of p-Hg1-хCdхTe (х=0.22) implanted with arsenic ions with 190 keV energy and fluence 1012, 1013, and 1014 cm-2. The vacancy-doped p-type samples were obtained with thermal annealing (220 0C, 24 h) at low mercury pressure in helium atmosphere of as-grown n-type sample. The microstructure observations were performed with transmission electron microscopy in bright field and high-resolution modes. It was found that after the implantation radiation-damaged areas in all studied samples were very similar and consisted of three characteristic sub-layers: a sub-surface layer with low defect density, a deeper layer with big dislocation loops and a deeply buried layer with small dislocation loops. The characteristic sizes of these regions and the density of radiation-induced nano-defects (dislocation loops) depended on the ion fluence. These data confirm the results of the electrical measurements of the concentration of radiation donor defects that were created by interstitial mercury atoms, which were released under implantation, with dislocation loops.