GaAs epitaxial layers obtained by close-spaced vapor transport in H2 + H2O and H2 + CO2 ambients: Fine control of the growth rate and its effect on the electrical properties of the layers

In view of developing the close-spaced vapor transport technique (CSVT) to obtain III/V homojunction solar cells, it is necessary to finely control the growth rate of GaAs epitaxial layers. This has been performed either by controlling the water vapor pressure, injected in the reactor along with H2, in H2 + H2O ambient, or by controlling the water vapor pressure generated in situ by the reaction of H2 + CO2 in the reactor. For H2 + CO2 ambient, , controls according to the following reaction: . The growth rates calculated with a diffusion controlled model are in agreement with the experimental values for both ambients, including the observation of a maximum in the evolution of the growth rate with , Controlling the growth rate of GaAs by changing affects the carrier density (NA–ND) of p-type layers grown from Zn-doped GaAs sources. In both ambients (NA–ND) is a function of . Such a behavior is also obtained for the calculated carrier densities. It is the result of the transport of Zn as ZnO in CSVT. In H2 ...