Investigation of the electrical characteristics of reteroepitaxial structures as function of microrelief and manufacturing technology features

We studied, over a vide (77-400 K) temperature range, 1- V curves of photoelectric converter (solar cell) prototypes made on the basis of the P-Al:r;Gal_xAs-p-GaAs-nGaAs- n+ -GaAs heteroepitaxiai structures grown on smooth or microre! ief n'" -GaAs substrates using the standard liquid phase epitaxy (LPE) and the capillary LPE from confined volume. At temperatures 900K the tunnel component of forward current was predominant in all the smooth samples studied, up to voltages about 1 V, while at room temperature all the three components (diffusion, recombination, tunnel) of forward current were afthe same order. This is evidenced, in particular, by the dependencies of the effective ideality factor of 1-V curves on the applied voltage. Predominance of the runnel currenr component in a wide temperature range at small biases was observed for all the solar cells obtained on textured n + -GaAs substrates. At that an additional factor favoring increase of the tunnel current component was reliefirregulariries of small radii of curvature.