|AVS 57th International Symposium & Exhibition|
|Thin Film||Monday Sessions|
|Session:||ALD: Energy Applications|
|Presenter:||B. Hoffmann, Institute of Photonic Technology, Germany|
|Authors:||B. Hoffmann, Institute of Photonic Technology, Germany
V.A. Sivakov, Institute of Photonic Technology, Germany
G. Broenstrup, Institute of Photonic Technology, Germany
F. Talkenberg, Institute of Photonic Technology, Germany
S.H. Christiansen, Max Planck Institute for the Science of Light, Germany
|Correspondent:||Click to Email|
Silicon nanowire (SiNW) ensembles with vertical geometry have been realized using wet chemical etching of bulk silicon wafers (n-Si(100)) with an etching hard mask of silver nanoparticles that are deposited by wet chemical electroless deposition on silicon surfaces.
The new concept of the solar cell is based on the semiconductor-insulator-semiconductor (SIS) layer sequence produced by Atomic Layer Deposition (ALD). A thin tunnelling oxide (SiO2, Al2O3) with a thickness of 5-20 Å and a 300 nm transparent conductive oxide (Al doped ZnO or In doped SnO2) around 1D silicon nanostructures have been realized using Plasma Assisted ALD approach (Oxford Plasma, OpAL).
The first prototype reached an open-circuit voltage of 80mV and a short-circuit current density of 23mA/cm2.
The influence of the thickness and chemical nature of the tunnelling oxide will be discussed. Back side contacts of Ti/Al or Ti/Ag were realized using sputtering. From literature it is known that the planar SIS solar cell can reach an energy conversation efficiency of approx 15%. Absorption of visible and infra-red light is significantly enhanced in nanowires compared to planar layers of identical thickness. Thus, wet chemically etched silicon nanowires have the potential for even higher energy conversation efficiencies compared to the planar SIS solar cells. The morphology, crystallographic and surface structure, optical and solar cell properties will be presented and discussed in details.