ISSN:
1432-0630
Keywords:
72.40
;
73
;
85
;
60
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Abstract The electrical properties ofn +-window layers inp-i-n a-Si:H solar cells were characterised as a function ofn +-layer thickness, $$d_{n^ + } $$ , by measuring firstly the activation energyE a of the dark conductivity and secondly the built-in potentialV bi of the cells.E a was found to increase with decreasing $$d_{n^ + } $$ attaining values as high as 0.8 eV for $$d_{n^ + } $$ ≅5nm; bulk values, e.g.E a ≅. 2eV in the amorphous andE a〈0.01 eV in the microcrystalline case, were only observed for $$d_{n^ + } $$ 〉20nm and for $$d_{n^ + } $$ 〉200nm, respectively. In contrast,V bi did not depend on $$d_{n^ + } $$ at all and was further found to be consistent with expectations based on the Fermi level positions in bulkn + andp +-material. As a consequenceE a in very thin films can no longer be considered as a measure of (E C −E F), the distance of the Fermi level from the conduction band edge. The apparent inconsistency inherent to theE a and theV bi results can be resolved by assuming that the deposition of then +-material proceeds via the growth and coalescence of small islands.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00632427
