Solar Applications: Back Contact

Overview – Molybdenum is metal layer that is regularly used as a back contact layer for inorganic thin film solar cells, such as CIGS and CdTe. The most common method used to deposit Molybdenum is sputtering, especially in high volume manufacturing environments. The advantages of a sputtered process include precise process control with scalable processes while still maintaining the ability to tune molybdenum layer properties for structure optimization. Reactive sputtering of molybdenum oxide has also been used as a buffer layer to improve the efficiency of thin film organic solar cells

Production Equipment

The SprintFlex

  • Roll to Roll Substrates 200mm – 450mm wide.
  • Free Span or Drum Architecture
  • Ideal for Industrial Scale R&D or Pilot Scale Production.
  • 1-2 front side deposition sources – 0-2 Back Side sources

The Orion Series

  • Roll to Roll Substrates 200mm – 500mm wide.
  • Free Span or Drum Architecture
  • Pilot or Production Manufacturing
  • 1-6 front side deposition sources – 0-2 Back Side sources

The Horizon

  • Horizontal In-Line Deposition System with Load Lock Entry and Exit
  • Flat, rigid glass, metal or plastic  substrates
  • Configurable coating area for single or multiple substrates up to 2.2 Meters Wide
  • Configurable deposition sources

The Horizon V

  • Vertical In-Line Deposition System with Load Lock Entry and Exit
  • Configurable coating area for single or multiple substrates up to 2 meters tall.
  • Flat, rigid glass, metal or plastic  substrates
  • Configurable deposition sources

Custom
Mustang designs & manufactures custom systems to meet customer specifications.

 

 

Research & Development Systems

The Orion Complete
Designed for free-span deposition of multiple thin films up to 40cm wide. A great R&D solution, this unit has 7 multi-source deposition zones, allowing users to deposit all PV layers in a continuous roll-to-roll system.


Challenges
– Molybdenum deposition can appear simple when compared to the complex deposition of CIGS. However it is important not to trivialize the importance of properly controlling and optimizing the molybdenum layer. For CIGS cells, molybdenum forms the foundation for the solar cell layer stack and will influence doping (intentional doping or impurity diffusion), CIGS grain size, adhesion, and surface roughness. Similar challenges are encountered for substrate deposition of molybdenum for flexible CdTe cells. Improper molybdenum deposition parameters will damage the CdTe absorber when using traditional superstrate deposition on glass.

A single molybdenum recipe is not ideal for all layer structures.

 

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