Isolated A+ states in boron doped silicon under high compressive stress

Abstract Long-wavelength photoconductivity spectra of isolated A + states in B-doped Si under uniaxial [111] or [100] compressive stress have been studied at 1.5 K. Besides, far-infrared photoconductivity and adsorption spectra of acceptor states in the crystal have been measured to obtain the experimental ionization energy of the acceptor. The binding energy of the second hole in the A + center is rather close to, and a tittle less than, the theoretical value of 0.055 of the effective Rydberg obtained with the effective mass approximation.