19.1EP.02 - EFFECTIVE USE OF GERMANIUM - EXPRO+
Publication Date: 04-MAR-19
Program ref.: Technology Developme
Tender Type: C
Tender Status: INTENDED
Price Range: 200-500 KEURO
Budget Ref.: E/0901-01 - Technology Developme
Proc. Prop.: NO
Special Prov.: BE+DK+FR+DE+IT+NL+ES+SE+CH+GB+IE+AT+NO+FI+PT+GR+LU+CZ+RO+PL+EE+HU
Directorate: Directorate of Tech, Eng. & Quality
Department: Electrical Department
Division: Power Systems, EMC & Space Environ.Div
Responsible: Caon, Antonio
Products: Satellites & Probes / Power / Generation: Solar Photovoltaic ¿ BB / Solar Cells
Satellites & Probes / Power / Generation: Solar Photovoltaic ¿ C&P / Substrates, cover-glass, coatings, adhesives, ...
Techology Domains: Spacecraft Electrical Power / Power Generation Technologies / Photovoltaic Generator Technology
Industrial Policy Measure: C1 - Activities in open competition limited to the non-Larg...
Today, Ge is used as a growth template for III-V based solar cells and also serves as the lowest active junction. While the thickness of the Ge on solar cell level is around 140m, actually only 10-20m are really active. Therefore, in order to become thinner andlighter, solar cell manufacturers start to thin down the Ge wafers after cell processing by grinding, etching or lift-off processes(to reduce weight). However, this Ge waste is today not recovered since no economical process exists. Therefore, one idea to improve the use of Germanium is to effectively recover the Ge and assure a cost effective recycling stream. Another possibility to become lighter and reduce the amount of Ge is to start from a different growth template such as e.g. Silicon (Si) that is one of the most abundant materials on earth. Furthermore, it is s also cheaper and lightweight. However, Si wafers are not compatible for growing III-Vsolar cells directly on them. Therefore, a dedicated development is needed for that option or equivalent alternatives. In previous LCA studies, Germanium (Ge) has been identified as one of the major environmental hotspots of ESA's space missions. Ge is one of theCritical Raw Materials and the use of it (mainly driven by the solar cells) is the major contributor for the impact of the spacecraft in mineral resource depletion. Even though recycling processes exist to a certain extent (as a minimum within the Ge wafer manufacturer UMICORE) other Ge waste, e.g. Produced during the grinding process when solar cells are thinned, is today not fully recovered. This activity is an important step to mitigate the environmental impact of ESA space missions. This activity encompasses the following tasks: 1. Recycling a. Evaluate recycling concepts with regard to feasibility, ecology and economy b. Identify the best conceptand carry out practical tests c. Specify a recycling unit and implement the system into the production line 2. Investigate options to improve use of Ge such as Virtual substrate (e.g. Ge on Si substrate). a. Develop buffer layer to grade the virtual substrate, e.g. From Si to Ge b. Develop Ge growth on virtual substrate c. Growth of III-V solar cell structures on virtual substrates. d. Engineering tests on solar cell structures A Life Cycle Assessment of the two options (Recycling and Virtual substrate) need to be performed. A comparison of these alternatives with current technology and manufacturing processes is required. Procurement Policy: C(1) = Activity restricted to non-prime contractors (incl. SMEs). For additional information please go to EMITS news "Industrial Policy measures for non-primes, SMEs and RD entities in ESA programmes".