Internal strain analysis of CdTe thin films deposited by pulsed DC magnetron sputtering

Kaminski, Piotr; Abbas, Ali; Chen, C.; Yılmaz, Selin; Bittau, Francesco; Bowers, Jake W.; Walls, John M.

doi:10.1109/pvsc.2015.7356093

Cited by 4 publications

(3 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The voltage on the target is typically ≃800 V during the sputtering process although this value depends on the resistivity of the individual target used. The system is equipped with radiant heaters and the substrate temperature during deposition can be maintained at temperatures up to 250 ° C. This temperature and the use of relatively high working gas pressure with gas flows of 50 sccm has been found to minimize stress in the films [15].…”

Section: Methodsmentioning

confidence: 99%

Inert gas bubble formation in magnetron sputtered thin-film CdTe solar cells

et al. 2020

View full text Add to dashboard Cite

Cadmium telluride (CdTe) solar cells are deposited in current production using evaporation-based tech- niques. Fabricating CdTe solar cells using magnetron sputtering would have the advantage of being more cost-efficient. Here, we show that such deposition results in the incorporation of the magnetron working gas Ar, within the films. Post deposition processing with CdCl 2 improves cell efficiency and during which stacking faults are removed. The Ar then accumulates into clusters leading to the creation of voids and blisters on the surface. Using molecular dynamics, the penetration threshold energies are determined for both Ar and Xe, with CdTe in both zinc-blende and wurtzite phases. These calculations show that more Ar than Xe can penetrate into the growing film with most penetration across the (111) surface. The mechanisms and energy barriers for interstitial Ar and Xe diffusion in zinc-blende are determined. Barriers are reduced near existing clusters, increasing the probability of capture-based cluster growth. Barriers in wurtzite are higher with non-Arrhenius behaviour observed. This provides an explanation for the increase in the size of voids observed after stacking fault removal. Blister exfoliation was also modelled, showing the formation of shallow craters with a raised rim.

show abstract

Section: Methodsmentioning

confidence: 99%

Inert gas bubble formation in magnetron sputtered thin-film CdTe solar cells

et al. 2020

View full text Add to dashboard Cite

show abstract

“…The advantages of the magnetron sputtering process are the uniformity of the deposited layer, the high thin film density and the relatively low substrate temperatures used during the growth of the device. The sputter deposition of CdTe solar cell requires substrate temperatures of ~250ºC [6]- [9],compared to 400ºC to 500ºC reported for VTD [10], [11].…”

Section: Introductionmentioning

confidence: 99%

“…The disadvantages of using RF power lie in the complex system design and the slow deposition rates [12]. Recently we reported on a new process for the magnetron sputtering of CdTe [9]. This uses a pulsed DC power supply which overcomes many of the limitations of using RF power.…”

Section: Introductionmentioning

confidence: 99%

High rate deposition of thin film CdTe solar cells by pulsed dc magnetron sputtering

et al. 2016

Self Cite

View full text Add to dashboard Cite

• This paper has been accepted for publication and appears in revised form, ABSTRACTA new high rate deposition method has been used to fabricate thin film CdTe photovoltaic devices using pulsed dc magnetron sputtering. The devices have been deposited in superstrate configuration on to a commercial fluorine doped tin oxide transparent conductor on soda lime glass. The cadmium sulphide and cadmium telluride thin films were deposited from compound targets. The magnetrons were mounted vertically around a cylindrical chamber and the substrate carrier rotates so that the layers can be deposited sequentially. The substrates were held at 200ºC during deposition, a process condition previously found to minimize the stress in the coatings. Optimization of the process involved a number of parameters including control of pulse frequency, power and working gas pressure. The devices deposited using the process are exceptionally uniform enabling the CdTe absorber thickness to be reduced to ~1um. The asdeposited material is dense and columnar. The cadmium chloride treatment increases the grain size and removes planar defects. The microstructure of the films before and after activation has been characterized using a number of techniques including transmission electron microscopy, Energy Dispersive mapping and these measurements have been correlated to device performance. The deposition rate is much higher than can be obtained with radio-frequency sputtering and is comparable with methods currently used in thin film CdTe module manufacturing such as Vapour Transport Deposition and Close Space Sublimation. INTRODUCTION

show abstract

Exploring the impact of defect energy levels in CdTe/Si dual-junction solar cells using wxAMPS

Isah,

Doroody,

Rahman

et al. 2024

Sci Rep

View full text Add to dashboard Cite

A numerical analysis of a CdTe/Si dual-junction solar cell in terms of defect density introduced at various defect energy levels in the absorber layer is provided. The impact of defect concentration is analyzed against the thickness of the CdTe layer, and variation of the top and bottom cell bandgaps is studied. The results show that CdTe thin film with defects density between 1014 and 1015 cm−3 is acceptable for the top cell of the designed dual-junction solar cell. The variations of the defect concentrations against the thickness of the CdTe layer indicate that the open circuit voltage, short circuit current density, and efficiency (ƞ) are more affected by the defect density at higher CdTe thickness. In contrast, the Fill factor is mainly affected by the defect density, regardless of the thin film’s thickness. An acceptable defect density of up to 1015 cm−3 at a CdTe thickness of 300 nm was obtained from this work. The bandgap variation shows optimal results for a CdTe with bandgaps ranging from 1.45 to 1.7 eV in tandem with a Si bandgap of about 1.1 eV. This study highlights the significance of tailoring defect density at different energy levels to realize viable CdTe/Si dual junction tandem solar cells. It also demonstrates how the impact of defect concentration changes with the thickness of the solar cell absorber layer.

show abstract

Internal strain analysis of CdTe thin films deposited by pulsed DC magnetron sputtering

Cited by 4 publications

References 7 publications

Inert gas bubble formation in magnetron sputtered thin-film CdTe solar cells

Inert gas bubble formation in magnetron sputtered thin-film CdTe solar cells

High rate deposition of thin film CdTe solar cells by pulsed dc magnetron sputtering

Exploring the impact of defect energy levels in CdTe/Si dual-junction solar cells using wxAMPS

Contact Info

Product

Resources

About