Mapping spectroscopic ellipsometry of CdTe solar cells for property-performance correlations

Koirala, Prakash; Tan, Xinxuan; Li, Jian; Podraza, Nikolas J.; Marsillac, Sylvain; Rockett, Angus; Collins, R. W.

doi:10.1109/pvsc.2014.6925011

Cited by 10 publications

(10 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Through-the-glass spectroscopic ellipsometry P. Koirala et al and 26 ± 8 nm, respectively, for the as-deposited sample of this study [18]. Given that the 17 best fit key structural and optical property parameters highlighted in Figure 3 and Table II are all deduced simultaneously, it is of interest to corroborate their values as broadly as possible.…”

Section: Among the Optical Property Parameters Inmentioning

confidence: 65%

“…These differences are interpreted in terms of compressive stress and grain boundary scattering, the latter providing a grain size estimate, with both being near the optical detection limits. This optical analysis capability is more powerful for as‐deposited CdTe prepared by sputtering for which the stress is larger and the mean path is shorter, specifically 0.52 ± 0.07 GPa and 26 ± 8 nm, respectively, for the as‐deposited sample of this study .…”

Section: Resultsmentioning

confidence: 93%

See 1 more Smart Citation

Through-the-glass spectroscopic ellipsometry for analysis of CdTe thin-film solar cells in the superstrate configuration

Koirala

Yoon

et al. 2016

Prog. Photovolt: Res. Appl.

Self Cite

View full text Add to dashboard Cite

Polycrystalline CdS/CdTe thin-film solar cells in the superstrate configuration have been studied by spectroscopic ellipsometry (SE) using glass side illumination. In this measurement method, the first reflection from the ambient/glass interface is rejected, whereas the second reflection from the glass/film-stack interface is collected; higher order reflections are also rejected. The SE analysis incorporates parameterized dielectric functions ε for solar cell component materials obtained by in situ and variableangle SE. In the SE analysis of the complete cells, a step-wise procedure ranks the fitting parameters, including thicknesses and those defining the spectra in ε, according to their ability to reduce the root-mean-square deviation between the simulated and measured SE spectra. The best fit thicknesses from this analysis are found to be consistent with electron microscopy. Based on the SE results, the solar cell quantum efficiency (QE) can be simulated without any free parameters, and comparisons with measured QE enable optical model refinements as well as identification of optical and electronic losses. These capabilities have wide applications in photovoltaic module mapping and in-line monitoring.

show abstract

Section: Among the Optical Property Parameters Inmentioning

confidence: 65%

Section: Resultsmentioning

confidence: 93%

Through-the-glass spectroscopic ellipsometry for analysis of CdTe thin-film solar cells in the superstrate configuration

Koirala

Yoon

et al. 2016

Prog. Photovolt: Res. Appl.

Self Cite

View full text Add to dashboard Cite

show abstract

“…A wealth of information can be extracted from these types of RTSE measurements applied at a single spot on a sample surface, but additional property variations related to sample non-uniformity have also been obtained by ex situ mapping spectroscopic ellipsometry (SE) [ 23 , 24 , 25 , 26 ]. In mapping SE, the sample and multichannel ellipsometer, similar to the instrument used in RTSE studies, are mechanically translated with respect to the each other in one or more dimensions to obtain ellipsometric spectra as a function of spatial position.…”

Section: Introductionmentioning

confidence: 99%

“…In the case of Si:H, simplified structural models based on results from RTSE measurements are applied to probe subtle variations in material opto-electronic response such as the band gap of a-Si:H, film thickness, surface roughness thickness, and nanocrystallite fraction in mixed phase materials. These types of measurements have been applied to Si:H [ 23 , 24 ], cadmium telluride [ 26 ], and copper indium gallium diselenide [ 25 ] PV devices ranging from tens of square centimeters on the laboratory scale to full industrially prepared panels. Thus, improvements in understanding and quantifying the structural transition of Si:H from amorphous to nanocrystalline, as obtained from single spot in situ RTSE measurements, can be applied to develop more advanced optical models and more thoroughly analyze mapping SE measurements collected over larger areas.…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic Ellipsometry Studies of n-i-p Hydrogenated Amorphous Silicon Based Photovoltaic Devices

et al. 2016

View full text Add to dashboard Cite

Optimization of thin film photovoltaics (PV) relies on characterizing the optoelectronic and structural properties of each layer and correlating these properties with device performance. Growth evolution diagrams have been used to guide production of materials with good optoelectronic properties in the full hydrogenated amorphous silicon (a-Si:H) PV device configuration. The nucleation and evolution of crystallites forming from the amorphous phase were studied using in situ near-infrared to ultraviolet spectroscopic ellipsometry during growth of films prepared as a function of hydrogen to reactive gas flow ratio R = [H2]/[SiH4]. In conjunction with higher photon energy measurements, the presence and relative absorption strength of silicon-hydrogen infrared modes were measured by infrared extended ellipsometry measurements to gain insight into chemical bonding. Structural and optical models have been developed for the back reflector (BR) structure consisting of sputtered undoped zinc oxide (ZnO) on top of silver (Ag) coated glass substrates. Characterization of the free-carrier absorption properties in Ag and the ZnO + Ag interface as well as phonon modes in ZnO were also studied by spectroscopic ellipsometry. Measurements ranging from 0.04 to 5 eV were used to extract layer thicknesses, composition, and optical response in the form of complex dielectric function spectra (ε = ε1 + iε2) for Ag, ZnO, the ZnO + Ag interface, and undoped a-Si:H layer in a substrate n-i-p a-Si:H based PV device structure.

show abstract

“…Novel methods for control of deposition processes were developed. [8] UT will deposit baseline CdTe solar cells for contacts then deposited at UI and ODU. In addition completed devices with conventional back contacts will be produced and characterized at UT for comparison with the novel contact options.…”

Section: I21 Subtask 1: Deposition Of Cdte Solar Cellsmentioning

confidence: 99%

Novel Contact Materials for Improved Performance CdTe Solar Cells Final Report

Rockett

Marsillac

Collins

2018

Self Cite

View full text Add to dashboard Cite

This program has explored a number of novel materials for contacts to CdTe solar cells in order to reduce the back contact Schottky barrier to zero and produce an ohmic contact. The project tested a wide range of potential contact materials including TiN, ZrN, CuInSe2:N, a-Si:H and alloys with C, and FeS2. Improved contacts were achieved with FeS2. As part of understanding the operation of the devices and controlling the deposition processes, a number of other important results were obtained. In the process of this project and following its conclusion it led to research that resulted in seven journal articles, nine conference publications, 13 talks presented at conferences, and training of eight graduate students. The seven journal articles were published in 2015, 2016, and 2017 and have been cited, as of March 2018, 52 times (one cited 19 times and two cited 11 times).

show abstract

Mapping spectroscopic ellipsometry of CdTe solar cells for property-performance correlations

Cited by 10 publications

References 7 publications

Through-the-glass spectroscopic ellipsometry for analysis of CdTe thin-film solar cells in the superstrate configuration

Through-the-glass spectroscopic ellipsometry for analysis of CdTe thin-film solar cells in the superstrate configuration

Spectroscopic Ellipsometry Studies of n-i-p Hydrogenated Amorphous Silicon Based Photovoltaic Devices

Novel Contact Materials for Improved Performance CdTe Solar Cells Final Report

Contact Info

Product

Resources

About