Temperature dependence of diffusion length, lifetime and minority electron mobility in GaInP

Abstract

The heterointerface IV curves at different intensity illumination levels have been extracted from full IV curves of triple-junction GaInP/GaAs/Ge solar cell. For this purpose a special approach for multi-junction solar cells has been proposed. The solar cell equivalent circuit consisting of two parts-generation and connecting ones were considered. The generation part includes all photovoltaic p-n junctions, while connecting one incudes a resistance of the layers, spreading resistance, tunnel diodes and heterointerfaces. The equivalent circuit was used for analysis of «kink» free IV curves of Ge and GaAs solar cells. In this case the IV curves of connecting part are completely described by the spreading resistance. The analysis of GaInP/GaAs/Ge allows to obtain heterointerface IV curves and it has been shown that their shape depends on illumination level. The empirical formula was used for an approximation of heterointerface IV curves to show the nature of current flow mechanism which was established as tunneling one.

Doping dependence and anisotropy of minority electron mobility in molecular beam epitaxy-grown p type GaInP

“…This transport imaging approach in the SEM has been described in detail in earlier work. 1,2 Excess carriers created at a point will diffuse and some fraction will recombine along the way, over a characteristic distance given by the minority carrier diffusion length. By maintaining the spatial information in the recombination luminescence, L d can be obtained directly from the optical image.…”

Heavy and light hole minority carrier transport properties in low-doped n-InGaAs lattice matched to InP

“…This calculation was done using the Freefem++ finite element solving software. 2 The ends are the contacts with p = p in j on the left and p = p 0 on the right. The current crossing the top and bottom boundaries is set to zero, ∂p/∂z = 0.…”

“…The solutions were calculated using the Freefem++ finite element solving software. 2 An example Freefem++ input file, two-hole-diff-01v.edp, is included at the end of this appendix.…”

“…Several methods presently exist to measure these, including electron beam induced current (EBIC) along a cross-sectional pn junction, 1 cathodoluminescence (CL) measurements on double-heterostructures, [2][3][4] zero-field time-offlight 5,6 , surface phovotoltage 7,8 to name a few. Coupling these diffusion lengths to lifetime measurements typically obtained from time-resolved photoluminescence, time-of-flight experiments, or time-resolved CL measurements, 9 one can then infer minority carrier mobilities if both measurements are performed for a comparable excess carrier concentration.…”

Cross-sectional transport imaging in a multijunction solar cell

“…This allows direct visualization of carrier diffusion, drift, or luminescent coupling, i.e., any process that results in photon emission at a location is spatially removed from the point of excitation. Since it gives direct access to the transport of minority carriers in doped semiconductor materials, transport imaging with far-field collection has most recently been used to measure minority carrier diffusion lengths and associated minority carrier mobilities in GaInP as a function of both doping and temperature [2], [3]. This was accomplished by studying specially designed double heterostructures of GaInP, which is the top cell material in the highest efficiency multijunction devices, and imaging resulting transport in the plane.…”