Photovoltage Formation Across Si P-N Junction Exposed to Laser Radiation

Abstract Photovoltage formation across Si p-n junction exposed to laser radiation is experimentally investigated. Illumination of the junction with 1.06 μm wavelength laser radiation leads to formation of classical photovoltage U ph due to intense electronhole pair generation. When the photon energy is lower than the semiconductor forbidden energy gap, the photovoltage U is found to consist of two components, U = U f + U ph . The first Uf is a fast one having polarity of thermoelectromotive force of hot carriers. The second U ph is classical photovoltage with polarity opposite to U f . It is found that U f is linearly dependent on laser intensity. The classical photovoltage is established to decrease with the rise of radiation wavelength due to decrease in two-photon absorption coefficient with wavelength. Predominance of each separate component in the formation of the net photovoltage depends on both laser wavelength and intensity