We report on the influence of surface reconstruction on silicon dopant incorporation and transport properties during molecular-beam epitaxy of GaAs(Bi) alloys. GaAs(Bi) growth with an (n × 3) reconstruction leads to n-type conductivity, while growth with a (2 × 1) reconstruction leads to p-type conductivity. We hypothesize that the presence or absence of surface arsenic dimers prevents or enables dopant incorporation into arsenic lattice sites. We consider the influence of bismuth anions on arsenic-dimer mediated dopant incorporation and the resulting electronic transport properties, demonstrating the applicability of this mechanism to mixed anion semiconductor alloys.

We demonstrate an x-ray rocking curve method which allows detection of an asymmetry in the dislocation densities in an heteroepitaxial (001) zinc blende semiconductor layer. These dislocations exist on two types of slip systems with their misfit dislocation line segments oriented along either a [1−10] direction (type A) or a [110] direction (type B). An imbalance in the densities of dislocations on these slip systems produces an observable azimuthal variation in the rocking curve width for symmetric x-ray reflections. An approximate quantitative model allows the estimation of the dislocation densities on the two types of slip systems.

No abstract

Here we report on the elastic strains in ZnSe 1ÿ x Te x (x , 0.9) epitaxial layers grown using photo-assisted metalorganic vapor phase epitaxy on In 0.53 Ga 0.47 As/ InP (001) substrates. High-resolution x-ray diffraction was used to determine their composition and strain. At room temperature, we observed an apparent asymmetry in strains for tensile and compressive layers. However, when we accounted for the difference in thermal expansion between the substrate and epitaxial material, the growth temperature strain relaxation appears symmetric with respect to the sign of mismatch. The growth temperature strains are in agreement with the Matthews and Blakeslee (MB) model [J.W. Matthews and A.E. Blakeslee, J. Cryst. Growth 27, 118 (1974)] for both compressive (x . 0.6) and tensile (x , 0.4) layers. However, for the layers with composition in the range 0.4 , x , 0.6, the growth temperature strains exceed the values predicted by the MB theory. Apparently, low-mismatch layers experience a kinetic barrier to relaxation. The overall behavior can be fit by the relaxation model of Dodson and Tsao [B.W. Dodson and J.Y. Tsao, Appl. Phys. Lett. 51, 1325Lett. 51, (1987 using the values Cm 2 5 80 s ÿ 1 and g 0 5 10 ÿ 9 .

No abstract