skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Effect of heat treatments and window layer processing on the characteristics of CuInGaSe{sub 2} thin film solar cells

Abstract

Interaction between chemical bath deposited CdS and ZnO window layers are a focus of this paper. Low temperature anneals were used to follow the changes at the interface. Optical absorption spectra show that CdS and ZnO intermix upon annealing. When applied to ZnO/CdS/CuInGaSe{sub 2} thin film solar cells, changes in the short and long wavelength response were observed. The latter is attributed to an increase in the energy gap of the absorber by diffusion of S. The interdiffusion is shown to increase the short wavelength collection, and hence the current density of the devices. Photoluminescence data provides some indication of the quality of the interface.

Authors:
; ;  [1]
  1. National Renewable Energy Lab., Golden, CO (United States) [and others
Publication Date:
Research Org.:
National Renewable Energy Lab., Golden, CO (United States)
OSTI Identifier:
416131
Report Number(s):
NREL/TP-410-21091; CONF-960513-
ON: DE96007880; TRN: 96:006561-0027
DOE Contract Number:
AC36-83CH10093
Resource Type:
Conference
Resource Relation:
Conference: 25. photovoltaic solar energy conference, Washington, DC (United States), 13-17 May 1996; Other Information: PBD: May 1996; Related Information: Is Part Of NREL preprints for the photovoltaic specialists conference of IEEE twenty-five; Gwinner, D. [ed.]; PB: 172 p.
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; INTERFACES; DIFFUSION; CASCADE SOLAR CELLS; HEAT TREATMENTS; THIN FILMS; CADMIUM SULFIDES; ZINC OXIDES; COPPER SELENIDES; INDIUM SELENIDES; GALLIUM SELENIDES; ENERGY GAP

Citation Formats

Ramanathan, K., Contreras, M.A., and Tuttle, J.R. Effect of heat treatments and window layer processing on the characteristics of CuInGaSe{sub 2} thin film solar cells. United States: N. p., 1996. Web.
Ramanathan, K., Contreras, M.A., & Tuttle, J.R. Effect of heat treatments and window layer processing on the characteristics of CuInGaSe{sub 2} thin film solar cells. United States.
Ramanathan, K., Contreras, M.A., and Tuttle, J.R. 1996. "Effect of heat treatments and window layer processing on the characteristics of CuInGaSe{sub 2} thin film solar cells". United States. doi:. https://www.osti.gov/servlets/purl/416131.
@article{osti_416131,
title = {Effect of heat treatments and window layer processing on the characteristics of CuInGaSe{sub 2} thin film solar cells},
author = {Ramanathan, K. and Contreras, M.A. and Tuttle, J.R.},
abstractNote = {Interaction between chemical bath deposited CdS and ZnO window layers are a focus of this paper. Low temperature anneals were used to follow the changes at the interface. Optical absorption spectra show that CdS and ZnO intermix upon annealing. When applied to ZnO/CdS/CuInGaSe{sub 2} thin film solar cells, changes in the short and long wavelength response were observed. The latter is attributed to an increase in the energy gap of the absorber by diffusion of S. The interdiffusion is shown to increase the short wavelength collection, and hence the current density of the devices. Photoluminescence data provides some indication of the quality of the interface.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 1996,
month = 5
}

Conference:
Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that hold this conference proceeding.

Save / Share:
  • Interaction between chemical bath deposited CdS and ZnO window layers are a focus of this paper. Low temperature anneals were used to follow the changes at the interface. Optical absorption spectra show that CdS and ZnO intermix upon annealing. When applied to ZnO/CdS/CuInGaSe{sub 2} thin film solar cells, changes in the short and long wavelength response were observed. The latter is attributed to an increase in the energy gap of the absorber by diffusion of S. The interdiffusion is shown to increase the short wavelength collection, and hence the current density of the devices. Photoluminescence data provides some indication ofmore » the quality of the interface.« less
  • In the conventional CdS/CdTe device structure, the poly-CdS window layer has a bandgap of {approx}2.4 eV, which causes absorption in the short-wavelength region. Higher short-circuit current densities (Jsc) can be achieved by reducing the CdS thickness, but this can adversely impact device open-circuit voltage (Voc) and fill factor (FF). Also, poly-CdS film has about 10% lattice mismatch related to the CdTe film, which limits the improvement of device Voc and FF. In this paper, we report a novel window material: oxygenated amorphous CdS film (a-CdS:O) prepared at room temperature by rf sputtering. The a-CdS:O film has a higher optical bandgapmore » (2.5-3.1 eV) than the poly-CdS film and an amorphous structure. The preliminary device results have demonstrated that Jsc of the CdTe device can be greatly improved while maintaining higher Voc and FF. We have fabricated a CdTe cell demonstrating an NREL-confirmed Jsc of 25.85 mA/cm2 and a total-area efficiency of 15.4%.« less
  • We investigated the damp heat (DH) stability of CuInGaSe2 (CIGS) solar cells as a function of thickness of the Al-doped ZnO (AZO) window layer from the 'standard' 0.12 μm to a modest 0.50 μm over an underlying 0.10-μm intrinsic ZnO buffer layer. The CIGS cells were prepared with external electrical contact using fine Au wire to the tiny 'standard' Ni/Al (0.05 μm/3 μm) metal grid contact pads. Bare cell coupons and sample sets encapsulated in a specially designed, Al-frame test structure with an opening for moisture ingress control using a TPT backsheet were exposed to DH at 85oC and 85%more » relative humidity, and characterized by current-voltage (I-V), quantum efficiency (QE), and (electrochemical) impedance spectroscopy (ECIS). The results show that bare cells exhibited rapid degradation within 50-100 h, accompanied by film wrinkling and delamination and corrosion of Mo and AlNi grid, regardless of AZO thickness. In contrast, the encapsulated cells did not show film wrinkling, delamination, and Mo corrosion after 168 h DH exposure; but the trend of efficiency degradation rate showed a weak correlation to the AZO thickness.« less