PHYSICS BASED STUDIES ON THE UNIQUE PROPERTIES OF RADIATION INDUCEDDOMINANT RECOMBINATION CENTER IN InGaP SPACE SOLAR CELLS

摘要

We have performed detailed studies on the stability of the defect H2 under various biases to clarify thedependence of the reaction rates on the position of the Fermi level in the absence of minority-carrier injection and recombination. The dependence of the annealing rates on electrical and optical injection current densities has been analyzed at different temperatures by using deep level transient spectroscopy (DLTS), thermally stimulatedcapacitance (TSCAP), deep level optical spectroscopy (DLOS), and photo-capacitance (PHCAP). The energy ofmulti-phonon emissions due to e-h recombination at the H2 center is evaluated as 1.3eV (Eg – ( ΔEthH2 – Δecap:hH2) = 1.85eV - (0.55-0.06eV)) obtained from the configuration coordinate diagram. The capture cross section of electron is about 4 orders of magnitude larger than the hole-capture cross section. The photo-ionization energy (0.94eV) estimated by DLOS confirmed PHCAP experiments. The Frank-Condon shift value (the difference between photoionization energy 0.94eV and thermal ionization one 0.55eV) is 0.39eV, which indicates that this center is a strong electron-lattice relaxation type defect. A coherent picture of the minority-carrier injection annealing of the H2 center in view of the electrical and optical experimental data analysis is identified as recombination enhanced defect reaction (REDR) effect.