Investigation of InxGa1-xP and InxAl1-xP heterostructures for tandem-type solar cells

Abstract

Solar panels are widely used as power supply for the spacecraft. One solar cells is formed by three dozen nanoepitaxial layers based on III-V materials that form InGaP/InGaAs/Ge junctions. In current paper the results of InxGa1-xP and InxAl1-xP thin samples investigation with different indium and gallium contents (X = 38 % − 53 %) on a germanium substrate and InxAl1-xP layers with different aluminum and indium contents (X = 46 % − 53 %) on germanium/gallium arsenide substrates. The samples were grown by MOCVD in a vertical reactor are discussed. The rocking curves obtained using high-resolution two-crystal X-ray diffractometry were investigated. The lattice parameters, the indium, aluminum and gallium atoms ratio was defined. The dependence of the solid phase composition (lattice parameter) on the gas composition phase is obtained. In the range X = 45 % − 53 % for the InxGa1-xP layer, in the range X = 46 % − 51 % for the InxAl1-xP layer a high perfection of the single-crystal structure is observed. It was established that the criterion for estimation of the grown structure quality along with the diffraction maxima mismatch can be the structure diffraction peak broadening. The results of the photoluminescence measurement show a uniform distribution over the sample entire surface.