Nanooptics and photonics

Nanosize radiation defects in arsenic implanted HgCdTe epitaxial films of n- and p-type 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 defect microstructure of molecular-beam epitaxy-grown epitaxial films of Hg1-хCdхTe (х=0.22) implanted with arsenic ions with 190 keV energy and 1014 cm-2 fluence. Two samples were studied: as-grown n-type sample and vacancy-doped p-type sample obtained with thermal annealing (220 0C, 24 h) at low mercury pressure in helium atmosphere. 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 area in two studied samples was identical and consisted of three characteristic layers, including a sub-surface layer with low defect density, a deeper layer with big dislocation loops and a deeply buried layer with small dislocation loops. Both the characteristic sizes of these regions and the types of radiation nano-defects were identical: dislocation loops, stacking faults, and crystal lattice disturbances. This confirms the conclusion that it is possible to study the electrical properties of radiation donor defects in p-type samples, since under real conditions in n-type samples they are masked by the high conductivity of the n-base.