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Enhanced current collection in back‐contacted back‐junction Si solar cells by overcompensating a boron emitter with a phosphorus base‐type doping
Author(s) -
Reichel Christian,
Granek Filip,
Hermle Martin,
Glunz Stefan W.
Publication year - 2010
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200925509
Subject(s) - common emitter , doping , materials science , optoelectronics , boron , quantum efficiency , solar cell , analytical chemistry (journal) , chemistry , organic chemistry , chromatography
Electrical shadings losses, resulting from a reduced minority charge carrier collection probability in regions without a collecting p – n junction, of industrially fabricated back‐contacted back‐junction silicon solar cells, are one of the main loss mechanisms. In order to minimize these losses, a local overcompensation of a boron emitter doping with a phosphorus base‐type doping can be applied to reduce the area without a collecting p – n junction and to increase the emitter coverage on the rear side considerably. The focus of the present investigation is to analyze the influence of the aforementioned solar cell design on the locally measured external quantum efficiency (EQE) and on the short‐circuit current. It has been found that for solar cells with a reduced base‐type doping area and an increased emitter coverage, electrical shading losses could be minimized significantly, resulting in very high short‐circuit currents J sc of 39.8 mA/cm 2 for a 1 Ω cm and 40.9 mA/cm 2 for a 10 Ω cm base material. This corresponds to a gain in J sc of 2.4 and 1.0 mA/cm 2 , respectively, compared to reference solar cells with a reduced collecting p – n junction area.