Plansee and TU Bergakademie Freiberg identify molybdenum’s key conductivity factors

Facebook
Twitter
LinkedIn
Reddit
Email

Molybdenum, commonly used as the back-contact material in CIGS solar cells, has been the subject of an in-depth study by sputtering target manufacturer Plansee, working in collaboration with TU Bergakademie Freiberg. Plansee’s results, presented at the ICMCTF Conference, identified the process errors and defect types present in molybdenum thin films that can have a detrimental effect on electrical conductivity.

Impurities and incorrect process temperatures during sputtering were said to be the main influences on electrical conductivity of the material. Impurities such as iron, nickel and chromium can, at high enough levels, reduce the electrical conductivity of the molybdenum thin film by more than 40%. Counteracting this effect is possible by ensuring the high purity of sputtering targets in the CIGS manufacturing process.

This article requires Premium SubscriptionBasic (FREE) Subscription

Try Premium for just $1

  • Full premium access for the first month at only $1
  • Converts to an annual rate after 30 days unless cancelled
  • Cancel anytime during the trial period

Premium Benefits

  • Expert industry analysis and interviews
  • Digital access to PV Tech Power journal
  • Exclusive event discounts

Or get the full Premium subscription right away

Or continue reading this article for free

Dislocations, or defects in the molybdenum crystal lattice, are said to be another major influence on electrical conductivity of molybdenum films. These dislocations, although necessary to enable the workability of the metals, can reduce the electrical conductivity by up to 14%. Plansee and TU Bergakademie Freiberg’s findings in this regard show that this effect can be halved by employing a process temperature of 150°C instead of room temperature.

Use of this higher temperature can also help reduce the effect of unavoidable interstitial impurities that collect on the lattice – usually consisting of nitrogen, oxygen and argon – which can reduce the electrical conductivity of the films by up to 12%. At 150°C, the tiny atoms are sufficiently energized to break free of the molybdenum lattice.

The testing of the molybdenum material was conducted by depositing the thin films on soda lime glass, thereby allowing the extraction of a basic characterization of the layers, measurement of the films’ electrical resistance and analysis of the films’ microstructure using Transmission Electron Microscopy (TEM) and X-ray diffraction (GAXRD). The group was headed by Professor David Rafaja of TU Bergakademie Freiberg’s Institute for Materials Science and Harald Köstenbauer, a developer of thin-film materials at Plansee.

Read Next

September 16, 2025
Sunotec has launched Sunotec Nordic to spearhead solar and hybrid renewable project development across the Nordic region.
September 16, 2025
The SPPC has launched a request for qualifications for 5.3GW of new renewable power capacity, of which solar will account for 3.1GW.
September 16, 2025
Chinese polysilicon producer GCL-Tech has entered into a strategic financing agreement with Infini Capital, a globally renowned investment institution backed by a Middle Eastern sovereign wealth fund.
Premium
September 16, 2025
At RE+, industry leaders pointed to the resilience of the US solar sector, despite challenges brought by the 'One Big, Beautiful Bill' Act.
September 16, 2025
IB Solar is investing INR30 billion (US$340 million) in a 4GW TOPCon solar cell and module manufacturing plant in Jewar, Uttar Pradesh.
September 16, 2025
Two of the major European solar trade associations, the European Solar Manufacturing Council (ESMC) and SolarPower Europe (SPE), have called for EU policymakers to take measures supporting European solar manufacturing.

Subscribe to Newsletter

Upcoming Events

Solar Media Events
September 30, 2025
Seattle, USA
Solar Media Events
October 1, 2025
London, UK
Solar Media Events
October 2, 2025
London,UK
Solar Media Events
October 7, 2025
Manila, Philippines
Solar Media Events
October 7, 2025
San Francisco Bay Area, USA