Title :
Electrical parameter changes in silicon solar cells induced by thermal donor formation
Author :
Ruiz, J. ; Cid, M.
Author_Institution :
Inst. de Energia Solar, Madrid, Spain
Abstract :
Statistical results of 450°C annealing experiments of variable duration, performed on n+pp+, 10 Ω-cm Czochralski silicon (Cz silicon), bifacial solar cells are presented. The specific temperature used is known to favor the nucleation of interstitial oxygen, creating the thermal donors, with important effects on the electrical properties of Cz silicon. Two distinct behaviors are observed with solar cells. The annealing during moderate time (below 4-5 h) leads, on average, to an improvement of the photovoltaic performances. Longer heat treatments (mainly above 8 h) induce an effective inversion of the base polarity (from p type to n type), with the net result of partially losing the precedent benefits. Both phenomena have been found to be permanent, provided further processes at higher temperatures are avoided
Keywords :
annealing; elemental semiconductors; impurity electron states; silicon; solar cells; 450 degC; Czochralski silicon; Si solar cells; annealing; base polarity inversion; bifacial solar cells; electrical properties; heat treatments; photovoltaic performances; semiconductor; thermal donor formation; Annealing; Conductivity; Crystals; Heat treatment; Photovoltaic cells; Photovoltaic systems; Silicon; Solar power generation; Surface treatment; Temperature sensors;
Conference_Titel :
Photovoltaic Specialists Conference, 1990., Conference Record of the Twenty First IEEE
Conference_Location :
Kissimmee, FL
DOI :
10.1109/PVSC.1990.111632