The device parameters (carrier lifetime, ideality factor), and physical parameters (built-in voltage, doping concentration) of silicon (Si) and gallium arsenide (GaAs/Ge) solar cells are measured at different temperatures using time domain technique. Carrier lifetime is calculated from open circuit voltage decay (OCVD). Built-in voltage and doping concentration are derived from the cell capacitance measured at different bias voltages. Ideality factor is derived from the I-V characteristics of solar cell. Carrier lifetime increases while built-in voltage decreases with increase in temperature. Ideality factor of the solar cell decreases with temperature. (C) 2005 Elsevier B.V. All rights reserved.