ABSTRACT
In the present study, detailed investigation on postdeposition halides treatment using CdCl2, CdI2, MgF2, MgCl2 and MgI2 is undertaken over thermally evaporated CdTe films. As-deposited films are subjected to halide treatment and subsequent annealing at 385°C. Halide activation induced grain growth mechanism is presented along with anions and cations roles on change in films properties and formation of different complexes. XRD patterns of all CdTe thin films exhibited polycrystalline nature with preferential cubic phased (310) plane except for CdI2 treated films where preferred reflection is appeared corresponding to (220) plane. Grain growth is observed with treatment employing amicable estimation tools. All films have a conspicuous ohmic character owing to linear I–V plots. Optical study reveals that CdCl2 treated CdTe films have higher absorbance and optical energy band-gap is measured out in the range 1.42–1.53 eV with halide treatment. Surface topography and PL study revealed to variations in surface roughness and photoluminescence peaks intensity with halide treatments. Film growth and treatment are validated by EDS analysis and FESEM images demonstrated explicit grain growth. Findings warrant amazing role of halide activation on film properties and CdCl2 is found a suitable surface treatment agent to CdTe films in order to develop better devices.
Graphical abstract
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Acknowledgments
Authors are highly grateful to the Sceince and Engineering Rsearch Board (SERB), New Delhi for financial assistance through Extramural Research (EMR) project (vide No. EMR/2017/003330) and to the DST-FIST through Mohanlal Sukhadia University, Udaipur for AFM and XRD facilities. The Ministry of Education, Government of India and Ministry of Higher Education, Govt. of Rajasthan through RUSA 2.0 R & I projects are acknowledged for PL facility and recurring expenses. The Center of Excellence for Industrial Textiles, PSG College of Technology, Coimbatore is also accredited for FESEM and EDS facilities.
Disclosure statement
The authors declare that they are having not known any conflict of interest that could have existed to impact this work financially and personally .