Maximization of the open circuit voltage for hydrogenated amorphous silicon n-i-p solar cells by incorporation of protocrystalline silicon p-type layers

Authors

R. J. Koval, Center for Thin Film Devices
Chi Chen, Center for Thin Film Devices
G. M. Ferreira, Center for Thin Film Devices
A. S. Ferlauto, Center for Thin Film Devices
J. M. Pearce, Center for Thin Film DevicesFollow
P. I. Rovira, Center for Thin Film Devices
C. R. Wronski, Center for Thin Film Devices
R. W. Collins, Center for Thin Film Devices

Document Type

Article

Publication Date

8-12-2002

Volume

81

Issue

7

Journal

Applied Physics Letters

First Page

1258

URL with Digital Object Identifier

10.1063/1.1499735

Last Page

1260

Abstract

In studies of hydrogenated amorphous silicon (a-Si:H) n-i-p solar cells fabricated by rf plasma-enhanced chemical vapor deposition (PECVD), we have found that the maximum open circuit voltage (Voc) is obtained by incorporating p-type doped Si:H layers that are protocrystalline in nature. Specifically, these optimum p layers are prepared by PECVD in the a-Si:H growth regime using the maximum hydrogen-to-silane flow ratio possible without crossing the thickness-dependent transition into the mixed-phase (amorphous+microcrystalline) growth regime for the ∼200 Å p-layer thickness. The strong dependence of the p-layer phase and solar cell V oc on the underlying i-layer phase also confirms the protocrystalline nature of the optimum Si:H p layer. © 2002 American Institute of Physics.