Characterization of space charge layer deep defects in n+-CdS/p-CdTe solar cells by temperature dependent capacitance spectroscopy

Kharangarh, Poonam R.; Misra, D.; Georgiou, G.; Chin, Ken K.

doi:10.1063/1.4800830

Cited by 19 publications

(5 citation statements)

References 40 publications

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“…Three characteristic activation energies, including ( E a1 = 0.368 ± 0.008 eV) for the HI‐etched device and ( E a1 = 0.430 ± 0.009 eV) and ( E a2 = 0.409 ± 0.023 eV) for the control device, are extracted from fitting with Equation . The values of 0.430 and 0.368 eV for the non‐HI and HI‐etched devices, respectively, are most likely related to H2‐type (hole trap) defects and their ionization by hole emission over the back‐contact potential barrier . Note that the E a1 values determined by TAS are in good agreement with the barrier heights that were calculated from J – V – T curves, with values of 0.404 and 0.377 eV for the control and HI‐etched devices, respectively …”

Section: Resultssupporting

confidence: 72%

The Effects of Hydrogen Iodide Back Surface Treatment on CdTe Solar Cells

Awni

Grice

et al. 2019

Solar RRL

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An appropriate electrical back contact in CdTe solar cells is crucial to achieving high power conversion efficiency. In this work, a facile back surface treatment method for CdTe solar cells using hydroiodic acid (HI) is developed, and the effects of HI etching on the CdTe surfaces investigated. The electrical properties of the CdTe absorber and interfaces are characterized by current–voltage, capacitance–voltage, admittance spectroscopy, and complex capacitance spectroscopy measurements. The HI‐etched devices show slightly higher apparent carrier concentrations than the control devices, suggesting an increased copper doping in the CdTe absorber. The potential barrier height of the back contact is reduced from 0.430 to 0.368 eV after the HI‐treatment, accompanied by reduced contact resistance and carrier recombination. Additionally, the HI‐treatment eliminates a defect signature at 0.409 eV. The HI‐treatment effects lead to improved power conversion efficiency through enhancement of the fill factor, the short circuit current, and open circuit voltage.

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Section: Resultssupporting

confidence: 72%

The Effects of Hydrogen Iodide Back Surface Treatment on CdTe Solar Cells

Awni

Grice

et al. 2019

Solar RRL

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“…The characteristic activation energy is calculated from fitting the curves of Arrhenius plot, Figure S5, by using Equation (3). The activation energy extracted from C-F spectra at temperature varies between 150 and 210 K (labeled E a1 ) and is most likely related to H2-type (hole trap) defects and their ionization by hole emission over the backcontact potential barrier, 12,26,[31][32][33] as confirmed by bias-dependent AS measurements showing that E a1 is altered by bias voltage ( Figure 6A). Note that the E a1 values determined by AS are in good agreement with the barrier heights calculated from IS analysis and J-V-T curves ( Figure S3).…”

Section: Admittance Spectroscopy Measurementsmentioning

confidence: 89%

Influences of buffer material and fabrication atmosphere on the electrical properties of CdTe solar cells

Awni

Song

et al. 2019

Progress in Photovoltaics

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The electrical properties such as interface energy barriers, defect energy levels, and densities dictate the performance of thin film solar cells. Here, we show that these properties can be quantified in cadmium telluride (CdTe) thin‐film solar cells using admittance spectroscopy‐based techniques. Our results reveal that the electrical properties in CdTe thin‐film solar cells depend on both buffer material and the fabrication atmosphere. We find that only a negligible front contact barrier exists at the CdS/CdTe front junction regardless of the fabrication atmospheres, while an obvious front barriers are observed at the ZnMgO (ZMO)/CdTe junctions. Both CdS/CdTe and ZMO/CdTe solar cells exhibit back contact barrier. The energy level of defects is shallower in CdS/CdTe cells than in ZMO/CdTe cells. The fabrication atmosphere influences the electrical properties, i.e., an oxygen‐free atmosphere reduces the front and back barrier heights and lowers the energy level of defects. The results provide critical insights for understanding and optimizing the performance of CdTe thin‐film solar cells.

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“…Solar cells are becoming an essential energy source for society as the demand for greener approaches for production of electricity is on the rise. Various types of solar cells include thin film solar cells, traditional silicon solar cells, 120 polymer solar cells, 24,118,119 CdTe solar cells, [121][122][123][124] and other novel solar cells 125,126 (shown in Figure 6A). GQDs can be used to fabricate solar cells due to their strong fluorescence, intense absorption in the UV range, and easy functionalization.…”

Section: Solar Cellsmentioning

confidence: 99%

Synthesis of luminescent graphene quantum dots from biomass waste materials for energy‐related applications—An overview

et al. 2022

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A review of the current developments in the synthesis of graphene fragments of porous carbon material by utilizing green precursors in the form of graphene quantum dots (GQDs) and their applications in energy storage devices such as supercapacitors, batteries, fuel cells, and solar cells is presented in this study. Two different approaches, including top‐down and bottom‐up, are discussed. The experimental approaches include hydrothermal or solvothermal method, microwave‐assisted method, electrochemical oxidation, controllable synthesis, oxidative cleavage, and carbonization from small molecules or polymers. The advantages and disadvantages of the green synthesis of GQDs are discussed. Current challenges and prospective applications of GQDs in energy‐related areas are presented. A brief outlook is provided for addressing the problems for further advancement of GQDs. It is anticipated that the results discussed in this study will lead to a better understanding of GQDs as well as their significant roles in developing innovative strategies and applications.

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Characterization of space charge layer deep defects in n+-CdS/p-CdTe solar cells by temperature dependent capacitance spectroscopy

Cited by 19 publications

References 40 publications

The Effects of Hydrogen Iodide Back Surface Treatment on CdTe Solar Cells

The Effects of Hydrogen Iodide Back Surface Treatment on CdTe Solar Cells

Influences of buffer material and fabrication atmosphere on the electrical properties of CdTe solar cells

Synthesis of luminescent graphene quantum dots from biomass waste materials for energy‐related applications—An overview

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