Equipment
We manufacture our solar cells in the clean room of the Ångström Laboratory. Here you can find information about the equipment we use to produce our solar cells.
How Are Solar Cells Manufactured?
The Division of Solar Cell Technology (SCT) utilizes a wide range of systems for the deposition and analysis of thin-film solar cells and materials.
Two key manufacturing techniques for our thin-film solar cells are co-evaporation and sputtering. These are also leading technologies in the industrial production of high-efficiency CIGS solar cells, offering the advantage of scalability for large-scale production.
Here, you can read more about the equipment we use to manufacture solar cells.
Deposition
Most of the deposition tools are managed by SCT and situated within a university shared cleanroom, MyFab Uppsala. These tools have all the processes needed to make complete chalcogenide thin film solar cells.
Solar Cell Absorber
(Ag, Cu)(In, Ga)Se2
A co-evaporator system utilizing mass spectrometer feedback to control the power of the sources. Alkali post-deposition treatments can also be conducted within the same system, with film thickness monitored by a quartz crystal microbalance (QCM) readout.
Chalcogenide Perovskites and Cu2ZnSnS4
A co-sputtering system with six target positions, capable of both pulsed direct-current (DC) and radio frequency (RF) sputtering. Deposition rates are monitored using QCM.
Post Sulfurization and Selenization
These processes can be performed in an external furnace, with sulfurization also possible in a small rapid thermal anneal furnace mounted on the co-sputtering system. This setup allows for sample transfer between the two without air exposure.
NaF Precursor
An evaporator system using QCM for precise film thickness control.
Contacting Layers
Buffer Layer or Transparent Electron Transport Layer (ETL)
CdS, ternary ZnO compounds, and ternary SnOₓ compounds can be deposited using atomic layer deposition (ALD) and heated chemical bath deposition (CBD). In-situ monitoring of the ALD process is possible using either QCM or ellipsometry.
Transparent Conducting Oxide (TCO)
A sputtering system with the capability of both DC and RF sputtering offers several options for TCO deposition, including indium tin oxide (ITO) and ZnO:Al. This system is part of the shared cleanroom facility, MyFab Uppsala.
Metals
Various metals, including Mo, Al, and Ni, are available through electron beam (e-beam) evaporation and sputtering. During evaporation, it is possible to use shadow masks for metal grid deposition. A wider variety of metals is available in the sputtering and evaporation tools located in the shared cleanroom facility, MyFab Uppsala
Miscellaneous
Anti-Reflection Coating
MgF₂ evaporator using QCM for film thickness control.
Cell Area Definition
A scribe tool that uses either a needle to mechanically remove layers or a green laser to ablate the layers away. Another option is to use the fully equipped lithography bay in the shared cleanroom facility, MyFab Uppsala, in combination with chemical etching of the TCO to define the cell area.
Glass Substrate Cleaning
Automated washer followed by a spin rinse dryer.
Analysis
Analysis tools are used to gain knowledge about everything from complete solar cells to the local arrangements of atoms within specific materials. Most of the tools listed below belong to SCT, but there is also a set of tools hosted elsewhere within the Ångström Laboratory that are frequently used by SCT.
Electrical and Optical
Current Density versus Voltage (JV)
One system uses a halogen lamp, and another setup uses an ABA solar simulator. Both systems have adjustable light intensity and a temperature-controlled stage.
External Quantum Efficiency (EQE)
Two systems that also offer the possibility to use biasing with light and electrical potential.
Current, Capacitance, Voltage, and Temperature (ICVT)
A system that uses a controllable light source in an otherwise dark chamber, an admittance reader, and a Peltier-controlled temperature stage.
Optical Transmittance and Reflectance
A system that uses wavelengths spanning from UV to IR, a monochromator, and an integrating sphere. The integrating sphere can be modified to eliminate the specular component of the reflectance.
Photoluminescence (PL)
Measures steady-state in both excitation and emission modes. The system also allows for electroluminescence if an external voltage source is used. This system belongs to the shared cleanroom facility, MyFab Uppsala.
Chemical and Structural
X-ray Fluorescence (XRF)
A system that uses a set of secondary targets to achieve a good signal-to-noise ratio for most elements.
Glow Discharge Optical Emission Spectroscopy (GDOES)
A system with very high element sensitivity, down to doping levels. The system provides depth profiles as it analyzes atoms continuously removed from the film.
X-ray Photoelectron Spectroscopy (XPS)
The system uses Al Kα radiation and has the capability to ion mill samples to create depth profiles. This system belongs to the shared cleanroom facility, MyFab Uppsala.
Electron Microscopy
The shared cleanroom facility, MyFab Uppsala, hosts a wide variety of electron microscopes for the analysis of micro- and nanoscale structures and their chemistries. SCT, for example, is a frequent user of scanning tunneling electron microscopy (STEM), energy dispersive X-ray spectroscopy (EDS), and electron beam induced current (EBIC), which provide very localized information on the chemical and electrical properties within a material, respectively. There is also an option to structure or slice materials using the electron microscope equipped with a focused ion beam (FIB).
X-ray Diffraction (XRD)
A wide variety of setups for both film and powder analysis are available within the shared X-ray laboratory hosted by the Department of Chemistry, Ångström.
Raman Spectroscopy
The system belongs to the Department of Chemistry, Ångström, and has a selection of light sources with different wavelengths.