期刊
SOLAR ENERGY
卷 159, 期 -, 页码 940-946出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.solener.2017.11.051
关键词
Oxygenated CdS; CdTe solar cells; Cadmium sulfate; TEM
资金
- UKERC through the EPSRC Supergen SuperSolar Hub
- U.S. Department of Energy through SunShot Foundational Program to Advance Cell Efficiency (F-PACE) [DE-AC36-08-GO28308]
- National Science Foundation [CBET-1706149]
- EPSRC [EP/N508457/1, EP/J017361/1, EP/P02484X/1, EP/N508433/1] Funding Source: UKRI
- Engineering and Physical Sciences Research Council [EP/J017361/1, EP/P02484X/1, EP/N508433/1, EP/N508457/1] Funding Source: researchfish
Oxygenated cadmium sulfide (CdS:O) is often used as the n-type window layer in high-performance CdTe heterojunction solar cells. The as-deposited layer prepared by reactive sputtering is XRD amorphous, with a bulk composition of CdS0.8O1.2. Recently it was shown that this layer undergoes significant transformation during device fabrication, but the roles of the individual high temperature processing steps was unclear. In this work high resolution transmission electron microscopy coupled to elemental analysis was used to understand the evolution of the heterojunction region through the individual high temperature fabrication steps of CdTe deposition, CdCl2 activation, and back contact activation. It is found that during CdTe deposition by close spaced sublimation at 600 degrees C the CdS:O film undergoes recrystallization, accompanied by a significant (30%) reduction in thickness. It is observed that oxygen segregates during this step, forming a bi-layer morphology consisting of nanocrystalline CdS adjacent to the tin oxide contact and an oxygen-rich layer adjacent to the CdTe absorber. This bilayer structure is then lost during the 400 degrees C CdCl2 treatment where the film transforms into a heterogeneous structure with cadmium sulfate clusters distributed randomly throughout the window layer. The thickness of window layer remains essentially unchanged after CdCl2 treatment, but a similar to 25 nm graded interfacial layer between CdTe and the window region is formed. Finally, the rapid thermal processing step used to activate the back contact was found to have a negligible impact on the structure or composition of the heterojunction region.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据