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1. Insights toward chlorine passivation effects on electronic structures of CdTe( 1¯00 ) and CdTe( 1¯1¯1¯ ) surfaces via atomistic modeling

   https://doi.org/10.1016/j.surfin.2021.101458  

   Nicholson, Anthony P. ; Shah, Akash ; Thiyagarajan, Aanand ; Sampath, Walajabad S. ( December 2021 , Surfaces and Interfaces)
2. Understanding the Role of CdTe in Polycrystalline CdSe x Te 1–x /CdTe‐Graded Bilayer Photovoltaic Devices

   https://doi.org/10.1002/solr.202100523  

   Shah, Akash ; Pandey, Ramesh ; Nicholson, Anthony ; Lustig, Zach ; Abbas, Ali ; Danielson, Adam ; Walls, John ; Munshi, Amit ; Sampath, Walajabad ( October 2021 , Solar RRL)

   Grading of bandgap by alloying CdTe with selenium to form a CdSe_xTe_1–x/CdTe‐graded bilayer device has led to a device efficiency over 19%. A CdSe_xTe_1–xabsorber would increase the short‐circuit current due to its lower bandgap but at the expense of open‐circuit voltage. It has been demonstrated that adding a CdTe layer at the back of such a CdSe_xTe_1–xfilm reduces the voltage deficit caused by the lower bandgap of absorber from selenium alloying while maintaining the higher short‐circuit current. This leads to a photovoltaic device that draws advantage from both materials with an efficiency greater than either of them. Herein, a detailed account using device data, ultraviolet photoelectron spectroscopy, electron microscopy, and first‐principles density functional theory modeling is provided, which shows that CdTe acts as an electron reflector for CdSe_xTe_1–x.

    

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3. The EDGE-CALIFA Survey: Spatially Resolved 13 CO(1–0) Observations and Variations in 12 CO(1–0)/ 13 CO(1–0) in Nearby Galaxies on Kiloparsec Scales

   https://doi.org/10.3847/1538-4365/acd840  

   Cao, Yixian ; Wong, Tony ; Bolatto, Alberto D. ; Leroy, Adam K. ; Rosolowsky, Erik ; Utomo, Dyas ; Sánchez, Sebastián F. ; Barrera-Ballesteros, Jorge K. ; Levy, Rebecca C. ; Colombo, Dario ; et al ( August 2023 , The Astrophysical Journal Supplement Series)

   We present¹³CO(J= 1 → 0) observations for the EDGE-CALIFA survey, which is a mapping survey of 126 nearby galaxies at a typical spatial resolution of 1.5 kpc. Using detected¹²CO emission as a prior, we detect¹³CO in 41 galaxies via integrated line flux over the entire galaxy and in 30 galaxies via integrated line intensity in resolved synthesized beams. Incorporating our CO observations and optical IFU spectroscopy, we perform a systematic comparison between the line ratio${\mathit{}}_{12/13}\equiv I{[}^{12}\mathrm{CO}(J=1\to 0)]/I{[}^{13}\mathrm{CO}(J=1\to 0)]$and the properties of the stars and ionized gas. Higher${\mathit{}}_{12/13}$values are found in interacting galaxies compared to those in noninteracting galaxies. The global${\mathit{}}_{12/13}$slightly increases with infrared colorF₆₀/F₁₀₀but appears insensitive to other host-galaxy properties such as morphology, stellar mass, or galaxy size. We also present azimuthally averaged${\mathit{}}_{12/13}$profiles for our sample up to a galactocentric radius of 0.4r₂₅(∼6 kpc), taking into account the¹³CO nondetections by spectral stacking. The radial profiles of${\mathit{}}_{12/13}$are quite flat across our sample. Within galactocentric distances of 0.2r₂₅, the azimuthally averaged${\mathit{}}_{12/13}$increases with the star formation rate. However, Spearman rank correlation tests show the azimuthally averaged${\mathit{}}_{12/13}$does not strongly correlate with any other gas or stellar properties in general, especially beyond 0.2r₂₅from the galaxy centers. Our findings suggest that in the complex environments in galaxy disks,${\mathit{}}_{12/13}$is not a sensitive tracer for ISM properties. Dynamical disturbances, like galaxy interactions or the presence of a bar, also have an overall impact on${\mathit{}}_{12/13}$, which further complicates the interpretations of${\mathit{}}_{12/13}$variations.

    

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4. Sputtered Aluminum Oxide and p + Amorphous Silicon Back-Contact for Improved Hole Extraction in Polycrystalline CdSe x Te 1-x and CdTe Photovoltaics

   https://doi.org/10.1109/PVSC40753.2019.8980466  

   Danielson, Adam ; Abbas, Ali ; Walls, John M. ; Holman, Zachary ; Sampath, Walajabad ; Munshi, Amit ; Onno, Arthur ; Weigand, William ; Kindvall, Anna ; Reich, Carey ; et al ( June 2019 , 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC))

   A thin layer of Al 2 O 3 at the back of CdSe x T e1-x /CdTe devices is shown to passivate the back interface and drastically improve surface recombination lifetimes and photoluminescent response. Despite this, such devices do not show an improvement in open-circuit voltage (V OC. ) Adding a p + amorphous silicon layer behind the Al 2 O 3 bends the conduction band upward, reducing the barrier to hole extraction and improving collection. Further optimization of the Al 2 O 3 , amorphous silicon (a-Si), and indium-doped tin oxide (ITO) layers, as well as their interaction with the CdCl 2 passivation process, are necessary to translate these electro-optical improvements into gains in voltage. 

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5. Doping CdSe x Te 1-x /CdTe Graded Absorber Films with Arsenic for Thin-Film Photovoltaics

   https://doi.org/10.1109/PVSC40753.2019.8981239  

   Munshi, Amit H. ; Guo, Jinglong ; Klie, Robert ; Sampath, Walajabad S. ; Danielson, Adam H. ; Swain, Santosh ; Reich, Carey L. ; Shimpi, Tushar M. ; McPherson, Seth W. ; Lynn, Kelvin G. ; et al ( June 2019 , 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC))

   CdTe thin-film photovoltaics have demonstrated some of the lowest costs of electricity generation owing to its low material cost and ease of manufacturing. However, the full potential of polycrystalline CdTe photovoltaics can only be realized if the open-circuit voltage can be increased beyond 1 V Open-circuit voltage ~850-900 mV has been consistently observed for state-of-the-art polycrystalline CdTe solar cells. Open-circuit voltage of over 1V has been demonstrated for single crystal CdTe devices by doping with Group V elements. Therefore, this study is aimed at understanding behavior of polycrystalline CdTe devices with arsenic doping, its activation and process and performance optimization in order to overcome current voltage limitations in CdTe solar cells. 

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