science24.com - Defects induced by oxygen and hydrogen in CdTe crystals

Search for content and authors

Defects induced by oxygen and hydrogen in CdTe crystals

A Kisiel ³, Andrzej Mycielski ², Jacek Polit ¹, E Sheregii ¹, J Cebulski ¹, M Piccinini ⁵, Augusto Marcelli ⁵, B V. Robouch ⁵, M Cestelli Guidi ^4,5, A Nucara ⁴

1. University of Rzeszow, Institute of Physics, Rejtana 16, Rzeszów 35-310, Poland
2. Polish Academy of Sciences, Institute of Physics, al. Lotników 32/46, Warszawa 02-668, Poland
3. Jagiellonian University, Institute of Physics (IF UJ), Reymonta 4, Kraków 30-059, Poland
4. Dipartimento di Fisica and Unita' INFM, Universita' di Roma "La Sapienza", Piazzale Aldo Moro 2, Roma 00185, Italy
5. °Laboratori Nazionali Frascati INFN (INFN), Via E. Fermi 40, Frascati 00044, Italy

Abstract

Actually, an important parameter to evaluate the quality of CdTe crystals is the content of residual amount of oxygen in high purity crystals. As a consequence, pure Cd and Te (99,999%) are used to growth CdTe monocrystals and thin films that are then purified by heating in a reduced hydrogen atmosphere. In this purification process is necessary to keep a balance between O and H so that to characterize oxygen and hydrogen contributions we applied both medium infrared (MIR) and far infrared (FIR) reflection spectroscopy. The infrared analysis is a very powerful method to investigate defects and in particular may obtain information on defects created in CdTe monocrystals grown from Cd and Te components purified in a hydrogen atmosphere before crystallization.It is thus interesting to consider the problem of asserting the presence of defects in semiconductor binary compounds, by observing consequences induced by distortions of their elemental tetrahedra due to the presence of vacancies and of insite atoms within the tetrahedra or other intersticial presence.Our model thus considers the system A(Vz_xZ_1-x) and (A_1-yVa_y)Z as composed of five defect tetrahedron configurations: {^zT_-1,^zT₊1},T₀,{^aT_-1 ,^aT₊1} where ^zT_-1 , ^aT_-1 tetrahedron with one vacancy, and ^zT₁, ^aT₁, with one interstitial are deformed tetrahedra.Detecting the five frequencies in presence would indicate the presence and amount of the defects being monitored.Reflectivity experiments were performed using a FTIR BRUKER Equinox 55 interferometer using both a standard Hg lamp and IR synchrotron radiation emitted by DAFNE the storage ring working at the INFN-LNF at Frascati.In the mid-infrared (500-3000 cm-1) region of these monocrystalline systems we observed the characteristic vibrational spectra of oxygen and hydrogen bounded to Cd and Te.Also a rich fine structure around the CdTe phonon frequency range in the far IR domain ,has been detected and analyzed.
[ABSTRACT TRUNCATED TO 2
[ABSTRACT TRUNCATED TO 2000 LETTERS]

Legal notice

Legal notice:

Copyright (c) Pielaszek Research, all rights reserved.
The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
In every case, proper references including Author(s) name(s) and URL of this webpage: https://science24.com/paper/2257 must be provided.

Defects induced by oxygen and hydrogen in CdTe crystals

Presentation: oral at E-MRS Fall Meeting 2004, Symposium F, by Jacek Polit See On-line Journal of E-MRS Fall Meeting 2004 Submitted: 2004-05-25 20:22 Revised: 2009-06-08 12:55

Presentation: oral at E-MRS Fall Meeting 2004, Symposium F, by Jacek Polit
See On-line Journal of E-MRS Fall Meeting 2004

Submitted: 2004-05-25 20:22 Revised: 2009-06-08 12:55