Thin Film Deposition for Energy Storage, Photovoltaic, and ULSI Devices
Thin film deposition is widely utilized in many different fields of technology. For example, for energy storage within electrochemical supercapacitors, the current technology involved deposition of metal oxide/sulfide thin films atop porous carbon electrodes, as illustrated below. Electrodeposition is a convenient and cost-effective method to form metal oxide/sulfide thin films.
Photovoltaic materials are the active materials within photovoltaic devices that convert sunlight into electricity for commercial and industrial usage. Energy production from sunlight has numerous advantages, including its widespread availability with no cost for fuel, and the lack of greenhouse gas production (i.e. CO2) associated with global warming. When exposed to sunlight, photovoltaic materials may absorb photons, which cause an electron to be excited from the conduction band to the valence band. The energy carried by this excited valence band electron can then be harnessed and converted to electricity.
Photovoltaic devices may contain a variety of different photovoltaic materials, including Si, CdTe, CuInxGa1-xSe2 (CIGS), and Cu2ZnSnS4 (CZTS). The figures below illustrate a CIGS photovoltaic device structure, which contains a variety of different thin film materials that serve numerous functions.
Electrochemical methods are often quite economical and effective for thin film deposition within photovoltaic devices. Electrochemical deposition methods include electrodeposition, electroless deposition, and galvanic deposition.