The Design and Fabrication of Photovoltaic Cells for the Creation of a Solar Panel
Solar power production comes chiefly in two forms, solar thermal and photo voltaic. Our project focuses on the development and fabrication of photovoltaic cells that will ultimately become part of a solar array or solar panel. Fabrication will take place at the Idaho Microfabrication Laboratory (IML) located at BSU and under the leadership of Pete Miranda. We will manufacture the photovoltaic cells using four inch diameter P-type silicon wafers. The electroconductivity for these wafers is quite high, at 0.5 ohm-cm which will allow the later formation of a PN junction. When the wafers arrive from the supplier they will likely suffer from a slight surface oxidation that might inhibit electrical flow so our first step is to strip off this native oxide and clean the wafer surface. Following that we will coat the wafer with a phosphorous impregnated liquid. The application of this liquid followed by a hot diffusion process will dope the wafer with a negative charge. A PN junction will then be formed within the substrate of the wafer where the positively doped silicon meets the new negatively doped silicon. This junction is sensitive to light. When light now strikes the surface of the wafer a voltage and current will be produced. Following this we will apply aluminum trace lines on the wafer surface to pick up as much electrical current as possible without covering too much of the wafer surface. We will then anneal the wafer to bond the aluminum to the substrate. After several wafers have been fabricated they will be connected together in a series-parallel configuration to achieve maximum power generation and placed inside a glass panel. As the first Sr. Design group to create solar cells in BSU history we wish to present this panel to BSU’s IML in an effort to inspire future student to begin where we will leave off, creating more efficient cells and larger panels.