Optical Characterization of GaInP p–i–n Solar Cells

Four p–i–n GaInP solar cells were grown by metal organic chemical vapor deposition (MOCVD) with different intrinsic layer thicknesses from 0.25 to 1 µm. A series of optical measurements, including electroreflectance (ER), photoluminescence (PL), electric luminescence (EL), and photocurrent (PC) measurements, have been performed to study the built-in electric field effect and to determine the suitable thickness of an intrinsic layer. The PL and EL spectra reflected the crystal quality of the GaInP layers. Furthermore, from the obtained ER spectrum, the built-in electric field in the intrinsic layer can be revealed. From the PC spectra under various bias voltages, the effect of built-in electric fields on the collection of photogenerated carriers has been studied.