The series resistance value of a photovoltaic (PV) cell required for high-intensity light and the effects of both the alpha parameter (the ratio of the open-circuit voltage to the bandgap) and temperature on conversion efficiency are investigated by a calculation method derived from the fundamental characteristics of PV cell. The PV cell characteristics for high-intensity laser light, including Si, GaAs, InGaAs PV cells and InGaAs uni-traveling-carrier photodiode (UTC-PD), are experimentally investigated. The small series resistance as large as 20-30 muOmega cm(2) and the suppression of recombination are important for obtaining higher conversion efficiency, especially for high-intensity laser light. (C) 2004 Elsevier B.V. All rights reserved.