Minority Carrier Recombination of Ordered Ga0.51In0.49P at High Temperatures

The minority carrier lifetime of high-quality ordered GaInP lattice matched to GaAs and the surface recombination velocity at its interface to AlInP were measured using time-resolved photo-luminescence (TRPL) in the temperature range of 77 500 K. The surface recombination velocity was found to be relatively low (under 500 cm/s) over the measured temperature range. The effective lifetime increased with temperature up to around 300 K, and then decreased in the 300 500 K range. The variations in the effective lifetime, caused by the variations in the bulk lifetime, are explained by considering the separate contributions of radiative and non-radiative recombination and their respective temperature dependencies. GaInP lattice matched to GaAs is an important material of the III-V semiconductor family that is used in high performance photovoltaic cells, in lightemitting diodes (LED's), heterojunctionbipolar-transistors (HBT's), and highelectron-mobility-transistors (HEMT's). It can also be considered for photon enhanced thermionic emission (PETE), which is a type of solar converter based on electron emission from semiconductors operating at high temperature. PETE converters may theoretically reach very high efficiencies of over 50% with the right combination of high-quality semiconductor materials and optimized operating conditions. Knowledge of the material electronic properties at high temperatures is thus crucial for the design and analysis of these devices and an important input parameter for performance simulations. In particular, photovoltaic cells in concentrator systems operate at temperatures above ambient and possibly up to 100C , whereas PETE cathodes are designed to operate at temperatures of several hundred degrees. Therefore, the electronic properties of the material and its interfaces should be characterized in the corresponding temperature range. The bulk minority carrier lifetime and the surface recombination velocity (SRV) are typically extracted using time resolved photo-luminescence (TRPL) measurements of samples with different thicknesses. PL measurements are widely used to characterize other materials such as GaAs . However, limited information is available for Ga0.51In0.49P which can be grown latticematched to GaAs with bandgap energies between 1.8 and 1.9 eV at room temperature. The bandgap is controlled by