Sputtered, oxygenated CdS window layers for higher current in CdS/CdTe thin film solar cells

Kephart, Jason M.; Geisthardt, Russell M.; Sampath, W. S.

doi:10.1109/pvsc.2012.6317737

Cited by 33 publications

(25 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…3,5,8,13 To optimize the buffer properties and to improve further device performance, a detailed understanding of the electronic and chemical structure is required. Soo et al 14 have shown the bulk of such films to consist of oxygen-free CdS nanocrystals and S−O complexes, which are speculated to be SO 3 2− and SO 4 2− complexes. To analyze the chemical structure of the S−O complexes in detail, X-ray photoelectron spectroscopy (XPS) and soft X-ray emission spectroscopy (XES) were used to study the speciesspecific composition of the surface and bulk, respectively.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Sulfur Bonding in CdS:O Buffer Layers for CdTe-based Thin-Film Solar Cells

Duncan

Kephart

Horsley

et al. 2015

ACS Appl. Mater. Interfaces

Self Cite

View full text Add to dashboard Cite

On the basis of a combination of X-ray photoelectron spectroscopy and synchrotron-based X-ray emission spectroscopy, we present a detailed characterization of the chemical structure of CdS:O thin films that can be employed as a substitute for CdS layers in thin-film solar cells. It is possible to analyze the local chemical environment of the probed elements, in particular sulfur, hence allowing insights into the species-specific composition of the films and their surfaces. A detailed quantification of the observed sulfur environments (i.e., sulfide, sulfate, and an intermediate oxide) as a function of oxygen content is presented, allowing a deliberate optimization of CdS:O thin films for their use as alternative buffer layers in thin-film photovoltaic devices.

show abstract

Section: Introductionmentioning

confidence: 99%

Characterization of Sulfur Bonding in CdS:O Buffer Layers for CdTe-based Thin-Film Solar Cells

Duncan

Kephart

Horsley

et al. 2015

ACS Appl. Mater. Interfaces

Self Cite

View full text Add to dashboard Cite

show abstract

“…The voltages of the two cells are similar, resulting in an improved efficiency from the CdS:O device. With similar fill factors, open circuit voltage, and improved current density; the PECSS source mimics improvements shown in creating CdS:O films with RF sputtering techniques.The PECSS process incorporated oxygen into the film to concentrations similar to Wu el al [4,5]. and increased cell efficiency by 1.2%.…”

mentioning

confidence: 84%

“…It is first utilized to widen the band gap of the window layer material (CdS) while simultaneously maintaining the rapid deposition rates of the original, non-plasma-assisted CSS process. In previous work by Wu et al and Kephart et al, high efficiency devices were generated by the addition of oxygen to the CdS [4,5]. Figure 1 shows the cross sectional geometry of a plasma source integrated into a CSS deposition source used at CSU [6,7].…”

Section: Introductionmentioning

confidence: 99%

Development of plasma enhanced closed space sublimation for the deposition of CdS:O in CdTe solar cells

Swanson

Hafner

Sampath

et al. 2013

2013 IEEE 39th Photovoltaic Specialists Conference (PVSC)

View full text Add to dashboard Cite

A hollow-cathode plasma-enhanced close space sublimation (PECSS) source was utilized to modify the CdS window layer material as it was being deposited for CdTe Solar cell fabrication. This was done by integrating PECSS into the CSU inline CdS/CdTe-cell fabricating system and by sublimating the CdS semiconductor material through a plasma discharge. To date oxygenated CdS (CdS:O) cells have been grown by sublimating CdS through a PECSS source operated on oxygen. Data are presented showing that PECSS CdS:O films have increased the band gap of the window layer therefore reducing absorption loss, increasing cell current, and improving efficiency by 1.2%.

show abstract

“…All semiconductor processes were completed in the Advanced Research Deposition System (ARDS) described previously [3]. The back contact consists of carbon-and nickel-containing acrylic paints.…”

Section: Methodsmentioning

confidence: 99%

“…Without a buffer and with 90 nm CdS, collection efficiency appears to degrade, but no clear pinholes can be observed using a 405 nm laser. previously described [3]. The CdS layer thickness of the nine devices made on each substrate is estimated using the QE at 450 nm relative to maximum QE of the device in the substrate center.…”

Section: Methodsmentioning

confidence: 99%

Reduction of window layer optical losses in CdS/CdTe solar cells using a float-line manufacturable HRT layer

Kephart

Geisthardt

et al. 2013

2013 IEEE 39th Photovoltaic Specialists Conference (PVSC)

Self Cite

View full text Add to dashboard Cite

Buffer, or high-resistance transparent (HRT) layers have been shown to increase the efficiency of CdS/CdTe solar cells. CdS/CdTe cells were fabricated on numerous float-linemanufacturable TCO and TCO/HRT-coated substrates. The behavior of the best-performing buffer layer was examined over a range of CdS thickness, and the device performance data show gradual dependence of open-circuit voltage and fill factor on CdS thickness below a critical value. The effect of fractional pinhole area is modeled, and it is proposed that pinholes do not dominate device behavior with thinner CdS, and instead band alignment effects explain the observed phenomena. Modeling indicates that the ohmic behavior of the buffer has a relatively small effect on devices with pinholes; instead, improving the diode quality of areas with thin or no CdS has a dominant effect.

show abstract

Sputtered, oxygenated CdS window layers for higher current in CdS/CdTe thin film solar cells

Cited by 33 publications

References 12 publications

Characterization of Sulfur Bonding in CdS:O Buffer Layers for CdTe-based Thin-Film Solar Cells

Characterization of Sulfur Bonding in CdS:O Buffer Layers for CdTe-based Thin-Film Solar Cells

Development of plasma enhanced closed space sublimation for the deposition of CdS:O in CdTe solar cells

Reduction of window layer optical losses in CdS/CdTe solar cells using a float-line manufacturable HRT layer

Contact Info

Product

Resources

About