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Thin Film CIGS and CdTe 

Photovoltaic Technologies: 

Commercialization, Critical 

Issues, and Applications 

Preprint 

H.S. Ullal and B. von Roedern 

To be presented at the 22nd European Photovoltaic Solar Energy 

Conference (PVSEC) and Exhibition 

Milan, Italy 

September 3–7, 2007 

Conference Paper 

NREL/CP-520-42058 

September 2007 

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Thin-Film CIGS and CdTe Photovoltaic Technologies: 

Commercialization, Critical Issues, and Applications 

Harin S.Ullal and Bolko von Roedern 

National Center for Photovoltaics 

National Renewable Energy Laboratory 

1617 Cole Boulevard, Golden, Colorado 80401 USA 

Tel: 303-384 6486; Fax: 303-384 6430; E-mail: harin_ullal@nrel.gov 

ABSTRACT: We report here on the major commercialization aspects of thin-film photovoltaic (PV) technologies based on 

CIGS and CdTe (a-Si and thin-Si are also reported for completeness on the status of thin-film PV). Worldwide silicon (Si) 

based PV technologies continues to dominate at more than 94% of the market share, with the share of thin-film PV at less 

than 6%. However, the market share for thin-film PV in the United States continues to grow rapidly over the past several 

years and in CY 2006, they had a substantial contribution of about 44%, compared to less than 10% in CY 2003. In CY 2007, 

thin-film PV market share is expected to surpass that of Si technology in the United States. Worldwide estimated projections 

for CY 2010 are that thin-film PV production capacity will be more than 3700 MW. A 40-MW thin-film CdTe solar field is 

currently being installed in Saxony, Germany, and will be completed in early CY 2009. The total project cost is Euro 130 

million, which equates to an installed PV system price of Euro 3.25/-watt averaged over the entire solar project. This is the 

lowest price for any installed PV system in the world today. Critical research, development, and technology issues for thinfilm CIGS and CdTe are also elucidated in this paper. 

Keywords: thin film, photovoltaics, amorphous silicon, cadmium telluride, copper indium diselenide, solar cell, module 

1.0 INTRODUCTION 

 Major advances have occurred in the past several years 

as thin-film photovoltaic (PV) technologies based on 

copper indium gallium deselenide (CIGS) and cadmium 

telluride (CdTe) continue to enter the market for various 

applications . (Amorphous silicon [a-Si] and thin-Si are 

included in this paper to give completeness on the status 

of thin-film PV.) The market share worldwide for thinfilm PV in CY 2006 was less than 6%. However, the 

market share for thin-film PV in the United States 

continues to grow rapidly and was reported at more than 

44% in CY 2006 (see Fig. 1; [1]). This number is mainly 

due to the aggressive growth in the manufacturing 

capacity of First Solar in Perrysburg, Ohio. In the case of 

a-Si, Uni-Solar in Auburn Hill, Michigan continues to 

play a leading role in the United States. Both companies 

report strong growth in CY 2006, and CY 2007 estimates 

should be even better. 

Figure 1: Thin-film PV market share versus calendar 

year 

 Several research, development, and, technology 

issues, both in thin-film CIGS and CdTe, are identified as 

the technology scales up to multi-megawatt production. 

In the case of thin-film CIGS absorber layers, about ten 

deposition processes are currently being developed 

worldwide. Issues such as standardization of the 

absorber-layer deposition needs to be addressed to help in 

large-scale thin-film PV manufacturing to lower the unit 

cost of module production. For thin-film CdTe, backcontact stability offers an opportunity for researchers to 

make more reliable thin-film CdTe PV products. 

 A number of applications are being pursued using thinfilm PV technologies, including building-integrated 

photovoltaics (BIPV), roof-top applications and utilityscale applications. 

2.0 COMMERCIALIZATION – THIN-FILM PV 

 Several thin-film PV companies in the United States 

and worldwide are actively involved in commercializing 

thin-film PV technologies using a-Si, CIGS, and CdTe. 

Table I summarizes the numerous groups in the various 

technology areas of a-Si, CIGS and CdTe that are 

actively involved in the scale-up and commercialization 

of thin-film PV technologies in the United States. 

Table 1: Thin Film PV Companies — USA 

Thin-Si CdTe CIS

Uni-Solar – MI First Solar – OH Global Solar – AZ 

Applied 

Materials – CA 

Primestar 

Solar – CO 

Miasole – CA 

Power Films – IA AVA Solar – CO Energy PV – NJ 

Energy PV – NJ Solar Fields – OH Ascent Solar – CO 

MV Systems – CO Canrom – NY ISET – CA 

XsunX – CA Ascentool – CA ITN/ES – CO 

OptiSolar – CA Nuvo Solar 

Energy – CO 

Daystar – NY 

Signet Solar – CA Zia Watt 

Solar – TX 

Nanosolar – CA 

Nano PV – NJ Heliovolt – TX 

MWOE Solar – OH Solo Power – CA 

Solexant – CA Solyndra – CA 

Proto Flex – CO RESI – NJ 

New Solar 

Ventures – NM 

Light Solar – NV 

Innovalight – CA Dow 

Chemicals – MI 

Nanogram – CA Stion – CA 

Soltaix – CA 

1
Some 16 companies in the United States are pursuing 

the development and commercialization of a-Si and thinSi PV products. Clearly, the U.S. leader is Uni-Solar 

(US), Michigan, with an installed capacity of 60 MW in 

CY 2006. An additional 60 MW with come online in CY 

2007, resulting in a cumulative capacity of 120 MW. US 

was supported by the National Renewable Energy 

Laboratory (NREL) in the technology development of the 

multi-junction solar cells. Applied Material (AM) 

supplies turn-key projects for the manufacture of singlejunction and tandem a-Si/nano Si also known as 

micromorph solar modules. Thus far AM has completed 

sales of more than 200 MW worldwide in countries such 

as China, India, Germany, Spain and Taiwan. There are 

15 CIGS companies using several deposition methods for 

the growth of the thin-film CIGS absorber layer. This 

offers both a challenge and opportunity for these 

emerging companies. Finally eight companies are scaling 

up the thin-film CdTe PV technology. All these groups 

are U.S.—based thin-film PV companies. 

 First Solar (FS) is clearly the world leader in all thinfilm PV technology development and global sales. They 

have an installed capacity of 90 MW in Perrysburg, Ohio 

for the manufacture of thin-film CdTe power modules, 

shown in Figure 2. FS has also recently started a new 

facility in Germany with an installed manufacturing 

capacity of 120 MW. 

Figure 2: First Solar’s 90-MW thin-film manufacturing 

plant in the USA 

 They are also installing an additional 240 MW 

manufacturing capacity in Malaysia to be completed in 

CY 2009. Thus, the total global target for FS is about 450 

MW by 2009 making it one of the leading PV companies 

in the world. Incidentally, NREL awarded the first 

subcontract to the predecessor company — Solar Cells, 

Inc, Ohio for the technology development of thin-film 

CdTe solar cells and modules in 1991and has since 

supported SCI and FS in the technology development for 

commercializing thin-film PV products. Figure 3 shows 

FS’s manufacturing cost for thin-film CdTe PV modules. 

As economies-of-scale have been realized, the 

manufacturing cost has dropped substantially from $-

2.94/W (6-MW) in CY 2004 to $-1.25/W (90 MW) at 

present (2), shown in Fig. 3. The target manufacturing 

cost is expected to be $-0.70/W due to improvements in 

productivity, module efficiency, and yield by CY 2012, 

thus making it potentially price competitive with gridparity electricity. 

Figure 3: Thin-Film CdTe manufacturing capacity and 

cost reduction versus calendar year 

 Worldwide, five companies are presently offering 

commercial thin-film PV CIGS products: Wurth Solar, 

(Germany), Global Solar, (USA), Honda, (Japan), Showa 

Shell, (Japan), and Sulfurcell, (Germany). The production 

capacity ranges between 5 and 27 MW per year. Also, 

worldwide, about 34 companies are actively developing 

thin-film CIGS PV technologies. These companies are 

using about ten different deposition methods for growing 

the thin CIGS absorber layers, as is shown in Table II. 

The absorber layer for commercial products uses either 

co-evaporation or the two-stage process such as the 

deposition of the precursors by sputtering followed by 

selenization. All companies use Mo as the back contact 

deposited by sputtering, and the majority use ZnO as the 

front contact deposited either by sputtering or chemical 

vapor deposition. 

Table 2: Thin Film CIGS Technology 

Company Substrate Back 

Contact

Process Front 

Contact

Shell Solar Glass Mo Sputter/ 

Selenization

ZnO

Global 

Solar

Steel Mo Coevaporation ITO

Miasole Glass Mo Sputter ZnO

Würth 

Solar

Glass Mo Coevaporation ZnO

Avancis Glass Mo Sputter / RTP ZnO

Daystar 

Tech

Glass Mo Sputter ZnO

EPV Glass Mo Sputter/ 

Evaporation

ZnO

Ascent 

Solar

Polymer Mo Coevaporation ZnO

ISET Glass/Flex Mo Ink/Selenization ZnO

Nanosolar Flexible Mo Print / RTP ZnO

Heliovolt Glass/Flex Mo FASST ZnO

SoloPower Steel Mo ED / RTP ZnO

3.0 CRITICAL RESEARCH, DEVELOPMENT, AND 

TECHNOLOGY ISSUES 

 Several critical issues still need to be addressed as 

emerging and new groups develop thin-film PV 

technologies. For thin-film CIGS PV technologies, the 

following six issues are critical for developing low-cost 

and reliable products: (1) standardization of equipment 

for the growth of the CIGS absorber films, (2) higher 

module efficiencies, (3) prevention of moisture ingress 

for flexible CIGS modules, (4) columnar structure for 

CIGS deposited by alternative process for high efficiency 

cells and modules, (5) thinner absorber layers of less than 

1 micrometer or less and (6) CIGS absorber film 

stoichiometry and uniformity over large areas. For thin 

2
film CdTe technology, five key issues include: (1) 

standardization of equipment for deposition of the 

absorber layer, (2) higher module efficiency, (3) backcontact stability, (4) reduced absorber layer thickness to 

less than 1 micrometer and (5) control of uniformity over 

large area. 

4.0 APPLICATIONS AND PRODUCTION CAPACITY 

 As thin film PV technologies matures, applications get 

larger in size for installed solar arrays. First Solar, along 

with Juwi Solar, Germany, is installing a 40-MW thinfilm CdTe solar field in Saxony, Germany. The project, 

shown in Fig. 4, is currently under construction and will 

be completed by early CY 2009. Thus far, 6-MW of the 

solar field has been installed. When completed, this will 

be one of the largest solar fields in the world. The total 

price of this project is Euro 130 million. Thus, the 

installed PV system price is Euro-3.25 per watt, also the 

lowest installed price for any PV system in the world. 

Figure 5 shows a thin-film CIGS facade installed on a 

building by Honda in Japan. The system size is estimated 

around 22-kW. 

Figure 4: A 40-MW thin-film CdTe solar field being 

built in Saxony, Germany to be completed in early CY 

2009 

Figure 5: Building-integrated thin-film CIGS façade on a 

Honda building in Japan 

 It is estimated that by 2010, the production capacity for 

thin-film PV technologies worldwide will be more than 

3700 MW, as depicted in Table III. The table in divided 

into various regions of the world. The United States — is 

estimated at 1127 MW, Japan at 1312 MW, Europe at 

793 MW and Asia at 472 MW for thin-film PV 

production capacity. 

 In breaking new, Sharp recently announced a 1000-

MW thin-film factory to be built in Japan by CY 2010. 

The technology, -presumably micromorph multijunction 

solar modules, will significantly reduce the 

manufacturing cost of PV, making it potentially more 

price-competitive with conventional energy sources. 

5.0 SUMMARY AND OUTLOOK 

 Rapid progress is being made by both a-Si- and CdTebased thin-film PV technologies in entering the 

commercial market. Several thin-film CIGS companies 

are also entering the market with power modules. In the 

United States, market share for thin-film was about 44% 

in CY 2006 and is expected to surpass Si sales in CY 

2007. Several critical research, development, and 

technology issues need to be addressed by emerging thinfilm PV companies as they plan to enter the market. The 

Table 3: Thin Film PV Capacity (2007-2010) 

3
projections for worldwide production capacity for all 

thin-film PV are estimated as more than 3700 MW in 

2010, with First Solar’s global target at 450 MW by 2009 

and Sharp’s target of 1000 MW by 2010. This 

economies-of-scale production capacity should 

substantially reduce the manufacturing price of the thinfilm PV products and potentially make solar electricity 

price-competitive with grid-parity electricity in the nottoo-distant future. 

6.0 ACKNOWLEDGMENTS 

 This work was supported by the U.S. Department of 

Energy under Contract No. DE-AC36-99G010337. The 

authors would like to thank the numerous managers, 

engineers, scientists, technicians whose data are included 

in this paper. 

7.0 REFERENCES 

[1] PV News – March –April, 2003 – 2007 

[2] Mike Ahearn, 1st PV Investors Conference, 

Munich, Germany; April 5, 2007 

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14. ABSTRACT (Maximum 200 Words)

We report here on the major commercialization aspects of thin-film photovoltaic (PV) technologies based on CIGS 

and CdTe (a-Si and thin-Si are also reported for completeness on the status of thin-film PV). Worldwide silicon (Si) 

based PV technologies continues to dominate at more than 94% of the market share, with the share of thin-film PV at 

less than 6%. However, the market share for thin-film PV in the United States continues to grow rapidly over the past 

several years and in CY 2006, they had a substantial contribution of about 44%, compared to less than 10% in CY 

2003. In CY 2007, thin-film PV market share is expected to surpass that of Si technology in the United States. 

Worldwide estimated projections for CY 2010 are that thin-film PV production capacity will be more than 3700 MW. A 

40-MW thin-film CdTe solar field is currently being installed in Saxony, Germany, and will be completed in early CY 

2009. The total project cost is Euro 130 million, which equates to an installed PV system price of Euro 3.25/-watt 

averaged over the entire solar project. This is the lowest price for any installed PV system in the world today. Critical 

research, development, and technology issues for thin-film CIGS and CdTe are also elucidated in this paper. 

15. SUBJECT TERMS

PV; thin film; amorphous silicon; cadmium telluride; copper indium diselenide; solar cell; module 

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