Control of point defects and arsenic clusters in low-temperature grown GaAs by isovalent impurity doping

We show that isovalent indium impurity doping can be employed to control excess-arsenic-related point defects and arsenic clusters in GaAs films grown by molecular-beam epitaxy at low temperature. In respect of arsenic excess, indium doping was found to be equivalent to a decrease in the growth temperature, but provided better crystalline quality of the material. Indium delta-doping was used to create two-dimensional sheets of arsenic clusters in the GaAs matrix. We demonstrate a 30-period superlattice of two-dimensional cluster sheets separated by cluster-flee spacers and two cluster sheets sandwiched between n- and p-GaAs layers grown at conventional temperature.