Fabrication and study of the properties of GaAs layers doped with bismuth

Pulsed laser deposition in vacuum at 220$^\circ$ C of GaAs layers heavily doped with Mn and/or Bi has been used to form nanostructures on $i$-GaAs (100) substrates. It is shown that, for the electrical activation of manganese, it is expedient to use subsequent annealing with an excimer laser pulse with a wavelength of 248 nm and a duration of 30 ns. The structures show an anomalous Hall effect with a hysteresis loop on the magnetic field dependence up to a Curie temperature of about $\sim$70 K. Negative magnetoresistance is observed up to temperatures of $\approx$150 K. Bismuth does not prevent the activation of Mn atoms during annealing and contributes to an increase in the coercive field of the GaMnAs ferromagnetic semiconductor.