Skip to main content
European Commission logo print header

STUDY ON THE APPLICABILITY OF THE IONIZED CLUSTER BEAM DEPOSITION TECHNOLOGY FOR GAAS THIN FILM SOLAR CELLS.

Ziel

GAAS THIN FILM SOLAR CELLS HAVE SHOWN THEIR POTENTIAL FOR HIGH EFFICIENCY ABOVE 10%. THEY ARE CONSIDERED FOR COMPONENTS IN TANDEM SOLAR CELLS. PROBLEMS HAVE BEEN FOUND REGARDING DEPOSITION TEMPERATURES CRYSTALLITE CONFIGURATION AND GRAIN BOUNDARIES.

IT IS THE AIM OF THE PROPOSED WORK TO DEMONSTRATE THAT A NEW, ION-ASSISTED DEPOSITION PROCESS, "ION CLUSTER BEAM" DEPOSITION (ICB) CAN LEAD TO SIGNIFICANTLY IMPROVED GAAS THIN FILM SOLAR CELLS AT LOWER SUBSTRATE TEMPERATURES THAN NEEDED IN THE PAST.

IN ICB DEPOSITION THE MATERIAL, E.G. GA AND AS IS TRANSPORTED TOWARDS THE SUBSTRATE IN THE FORM OF SMALL CLUSTERS CONTAINING APPROX. 100 ATOMS, WHICH ARE CHARGED BY ELECTRON BEAM AND ACCELARATED TOWARDS THE SUBSTRATE BY AN ELECTRIC FIELD. THE KINETIC ENERGY OF THE ARRIVING CLUSTERS, DECOMPOSING INTO ATOMS, REPRESENTS A "VIRTUAL TEMPERATURE", FACILITATING REACTION AND CRYSTALLITE GROWTH.

GAAS DEPOSITION TECHNOLOGIES RECENTLY HAVE FOUND INCREASED INTEREST UNDER THE AIM OF MONOLITHICALLY INTEGRATING GAAS AND SI TECHNOLOGIES FOR ELECTRONIC AND OPTOELECTRONIC APPLICATIONS. THIS WILL ALSO INFLUENCE GAAS THIN FILM SOLAR CELL DEVELOPMENT EFFORTS.

THE POTENTIAL FOR ACHIEVING ABOVE 10% EFFICIENCY FOR POLYCRYSTALLINE FILMS, CLOSE TO 20% FRO FILMS ON SI AND GE AND WELL ABOVE 20% FRO FILMS ON BULK GAAS HAS RECENTLY BEEN DEMONSTRATED.

IT IS THE AIM OF THE PROJECT TO DEPOSIT GAAS FILMS BY MEANS OF THE "IONIZED CLUSTER BEAM" DEPOSITION PROCESS, AND TO OPTIMIZE THEM INSOFAR, THAT FILMS SUITED FOR SOLAR CELL APPLICATION CAN BE OBTAINED AT LOWEST POSSIBLE SUBSTRATE TEMPERATURES.

THE PROCESS HAS BEEN DEFINED SO, THAT IN THE FIRST PHASE GA WILL BE DEPOSITED BY ICB AND AS WILL BE COEVAPORATED AS ELEMENT. THE COMPONENTS FOR THE PROCESS HAVE BEEN PURCHASED, DEVELOPED AND BUILT. AFTER INDIVIDUAL TESTS THEY HAVE BEEN INSTALLED WITHIN THE VACUUM VESSEL.

GAAS FILMS HAVE BEEN DEPOSITED ONTO COMMERCIAL GAAS WAFERS AT TEMPERATURES OF 580 C UNDER EXCESS AS-FLUX AT A DEPOSTITION RATE OF 2A/S. MAIN PARAMETER TO BE VARIED HAS BEEN THE ACCELERATION POTENTIAL FOR THE IONIZED CLUSTERS.

FIRST OPTIMISATION STEPS HAVE LED TO EPITAXIAL FILMS ON GAAS HAVING P-DOPING LEVELS AS LOW AS 10E12CM-E3 AND HOLE MOBILITIES OF UP TO 250CME2V-1S-1, AS DETERMINED FROM FILMS GROWN ON HIGH-RESISTIVITY WAFERS.

Thema/Themen

Data not available

Aufforderung zur Vorschlagseinreichung

Data not available

Koordinator

Battelle-Institut eV
EU-Beitrag
Keine Daten
Adresse
Am Römerhof 35
60486 Frankfurt am Main
Deutschland

Auf der Karte ansehen

Gesamtkosten
Keine Daten