Thin film technology has reached a maturity to achieve conversion efficiencies of the order of 22%. Among thin films, CdTe-based photovoltaic modules represent 80% of the total production. Nonetheless, some issues concerning back-contact are still open. In industrial process a chemical etching is required in order to make the CdTe film surface rich in Te. The Te-excess is fundamental in order to form a stable telluride compound with copper and to obtain an ohmic, low-resistance back-contact. Moreover, the Te-excess hinders the fast diffusion of copper in CdTe and its achievement of the junction region, preventing the destruction of the device. In this paper we study a ZnTe:Cu buffer layer deposited onto a CdTe film, characterized by a naturally Te-rich surface obtained with a particular chlorine heat treatment without any chemical etching. Copper diffusion and the CdTe/ZnTe:Cu interface were studied by x-ray photoemission spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF- SIMS) to deeply analyze the intermixing phenomena and copper behavior inside polycrystalline CdTe film.
Interface phenomena between CdTe and ZnTe:Cu back contact / Bosio, A.; Ciprian, R.; Lamperti, A.; Rago, I.; Ressel, B.; Rosa, G.; Stupar, M.; Weschke, E.. - In: SOLAR ENERGY. - ISSN 0038-092X. - 176:(2018), pp. 186-193. [10.1016/j.solener.2018.10.035]
Interface phenomena between CdTe and ZnTe:Cu back contact
Bosio A.
Membro del Collaboration Group
;Ciprian R.Membro del Collaboration Group
;
2018-01-01
Abstract
Thin film technology has reached a maturity to achieve conversion efficiencies of the order of 22%. Among thin films, CdTe-based photovoltaic modules represent 80% of the total production. Nonetheless, some issues concerning back-contact are still open. In industrial process a chemical etching is required in order to make the CdTe film surface rich in Te. The Te-excess is fundamental in order to form a stable telluride compound with copper and to obtain an ohmic, low-resistance back-contact. Moreover, the Te-excess hinders the fast diffusion of copper in CdTe and its achievement of the junction region, preventing the destruction of the device. In this paper we study a ZnTe:Cu buffer layer deposited onto a CdTe film, characterized by a naturally Te-rich surface obtained with a particular chlorine heat treatment without any chemical etching. Copper diffusion and the CdTe/ZnTe:Cu interface were studied by x-ray photoemission spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF- SIMS) to deeply analyze the intermixing phenomena and copper behavior inside polycrystalline CdTe film.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.