High-Efficiency Delta-Doped Amorphous Silicon Solar Cells Prepared by Photochemical Vapor Deposition

Abstract

Amorphous Si solar cells with delta-doped (δ-doped) p-layers were prepared by a multichamber photochemical vapor deposition (photo-CVD) system. By optimizing the structure of the δ-doped p-layer, a conversion efficiency of 12.3% (AM1) was obtained for small-area solar cells with a δ-doped p-layer using B2H6 as a dopant source. The δ-doped p-layers deposited with trimethylboron (TMB) and triethylboron (TEB) as new boron sources were characterized. It was found that the boron layers obtained with TMB by photo-CVD contain a large amount of carbon atoms which degrade the solar cell performance. Carbon contamination was suppressed both by the plasma CVD method with a gas mixture of TMB, H2 and He and by the photo-CVD method with TEB.

Threshold photoelectron spectroscopy of trimethylborane and its pyrolysis products

“…It is a potent candidate for materials applications 1 and is often deposited as a coating using the chemical vapor deposition (CVD) method. 2,3 Here, a stable precursor molecule is decomposed by heating or in a plasma to generate atoms that form a thin film. 4 Trimethylborane (TMB) has been investigated with respect to various CVD applications, such as formation of BC, 3 boron-doped diamonds, 5 and MgB 2 films.…”

15% enhancement of the photocurrent at the maximum power point of a thin film solar cell

“…27 Initially, doping was used mainly to enhance the contact properties and later also as a charge recombination layer in multi-junction cells. 27 Doping is also used in inorganic cells and one can nd examples showing insertion of d-doping in the transport layer [28][29][30] or a thin doped layer in the wetting layer (spacer) between quantum dots in the active region. 31,32 Here too, doping the transport layer resulted in enhancing either its conductivity 28 or charge selectivity.…”

Large-area ZnO films grown by photo-MOCVD and their application to a-Si solar cells

“…The thickness of ZnO films for TCO and for back reflector were 2.0pm and O.lpm, respectively. The delta doped p-layer was prepared by alternate deposition of a thin boron layer of 0.1-0.5 atomic layers and a 2-3nm thick undoped a-SiC:H layer [5]. A gradedband gap a-SiC:H layer was employed for the buffer layer [6].…”

“…The cell performances were measured under AM-1. 5 (100mW/cm2) illumination. doping concentration of ZnO film is a direct consequence of low conductivity of the film.…”