Berlin 2012 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 24: Poster Session: Ge/Si/SiC / III - V Semiconductors

HL 24.13: Poster

Montag, 26. März 2012, 16:00–19:00, Poster D

Lifetime measurements on III-V solar cell relevant materials — •Anja Dobrich¹, Klaus Schwarzburg¹, Elias Martinez¹, Marinus Kunst¹, and Thomas Hannappel^1,2,3 — ¹Helmholtz-Zentrum Berlin, Institut Solare Brennstoffe und Energiespeichermaterialien, D-14109 Berlin — ²TU Ilmenau, Institut für Physik, Fachgebiet Photovoltaik, D-98693 Ilmenau — ³CiS Forschungsinstitut für Mikrosensorik und Photovoltaik, D-99099 Erfurt

The lifetime of minority charge carriers in III-V relevant solar cell absorber materials is essential for the performance of solar cells. Suitable nondestructive methods to get informations about the electronic quality of the grown layers are the time resolved photoluminescence (TRPL) and transient microwave photoconductivity (TRMC). The lifetime of minority charge carriers generated by a laser pulse is measured and gives direct results about the material quality. Both methods should lead to the same results under similar excess charge carrier density conditions and deliver informations about the bulk material quality and the interface quality as well. However, if electric fields are generated caused by growth conditions in the structures to be examined (i.e. on interfaces) or p-n junctions in solar cell structures are investigated, the assumption of a homogeneous charge carrier distribution is no more valid and leads to the false interpretation of the measured results. With the help of some examples the influences of these effects should be demonstrated for the measured minority charge carrier lifetimes of MOVPE grown InP/InGaAs /InP test structures and solar relevant absorbers and structures in generally.