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CdTe absorber layers grown under Cd-rich conditions by MOCVD: Impact on surface morphology and structure
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Tom Dunlop ,
Ciaran Llewelyn ,
Michael Walls ,
Dingyuan Lu,
Gang Xiong,
Dan Lamb
Solar Energy Materials and Solar Cells, Volume: 282, Start page: 113440
Swansea University Authors:
Ochai Oklobia, Stuart Irvine, Tom Dunlop , Ciaran Llewelyn , Dan Lamb
Full text not available from this repository: check for access using links below.
DOI (Published version): 10.1016/j.solmat.2025.113440
Abstract
The analyses of surface morphology and microstructural properties of CdTe thin film absorber layers, deposited by metal organic chemical vapour deposition (MOCVD) on CdS/CdZnS/FTO-coated glass substrates as a function of different growth conditions (non–saturated or Cd–saturated growth condition and...
| Published in: | Solar Energy Materials and Solar Cells |
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| ISSN: | 0927-0248 1879-3398 |
| Published: |
Elsevier BV
2025
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| Online Access: |
Check full text
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| URI: | https://cronfa.swan.ac.uk/Record/cronfa68735 |
| Abstract: |
The analyses of surface morphology and microstructural properties of CdTe thin film absorber layers, deposited by metal organic chemical vapour deposition (MOCVD) on CdS/CdZnS/FTO-coated glass substrates as a function of different growth conditions (non–saturated or Cd–saturated growth condition and post–growth CdCl2 heat treatment) are presented. Scanning electron microscopy (SEM) images showed that the CdTe absorber surface morphology was relatively smoother with Cd-saturated growth compared to non-saturated conditions, while using a similar II/VI precursor partial pressure ratio. Microstructural characterisation using electron back scatter diffraction (EBSD) measurements indicate a strong influence of the II/VI ratios on the crystalline structure and degree of recrystallisation in Cd–saturated deposited CdTe absorber layers. CdTe absorber layers from a low II/VI ratio of 2 showed a strong Te(A1) Raman spectra band, characteristic of a Te rich composition, whilst a Cd–saturated composition was confirmed in the case of II/VI ratio of 4, as Te(A1) band was significantly suppressed. Cd–saturated grown CdTe:As (II/VI = 4), combined with a CdCl2 activation process at 440 °C, yielded optimum, highly randomized textured absorber with large grains. Reduced [111] oriented grains and suppression of Te(A1) mode was found to lead to higher VOC in devices. A high efficiency CdTe:As solar cell with a high VOC of 825 mV was measured based on the optimum growth condition for the absorber layers. |
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| Keywords: |
MOCVD; CdTe; Cd-saturated growth; Roughness; Microstructure; Texture randomization; Micro-Raman spectroscopy |
| College: |
Faculty of Science and Engineering |
| Funders: |
Funding provided by the Engineering and Physical Sciences Research Council (EPSRC), United Kingdom via the grant EP/W000555/1 and EPW00092X/1. The European Regional Development Fund (ERDF) and the Welsh European Funding Office (WEFO) which funded the 2nd Solar Photovoltaic Academic Research Consortium (SPARC II) and supported this research, is gratefully acknowledged. The authors also acknowledge support from First Solar, Inc. Access to characterisation equipment in Swansea University Advanced Imaging of Materials (AIM) facility, funded in part by the EPSRC (EP/M028267/1) and the European Regional Development Fund through the Welsh Government (80708) is acknowledged. Thanks also to Mr. Steve Jones for carrying out growth runs of the CdTe:As absorber layers, investigated in this work and for technical assistance. |
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113440 |