Abstract
Transport properties of Sn-doped Ga 0.47 In 0.53 As and Al 0.48 In 0.52 As epitaxial layers grown lattice matched to InP substrates by molecular-beam epitaxy (MBE) have been studied. Doping levels as high as 2×10 19 cm -3 have been achieved for both n-types Ga 0.47 In 0.53 As and Al 0.48 In 0.52 As. The carrier concentration varies proportionally with the arrival rate of Sn and the sticking coefficient of Sn in these ternary systems is estimated to be unity. For the same Sn arrival rate, the carrier concentrations in both ternary epitaxial layers are identical. Mobility studies showed that the results with MBE grown Sn-doped Ga 0.47 In 0.53 As layers are comparable to the best reported with liquid phase epitaxy (LPE). The variations of electron mobility as a function of carrier concentration are in excellent agreement with the results of the theoretical calculations involving the alloy scattering mechanism at both room and liquid-nitrogen temperatures. The electron mobility variation in Al 0.48 In 0.52 As epitaxial layers follows the same trend as that in Ga 0.47 In 0.53 As epilayers. For the same carrier concentration, however, the value is only 1/6 of that of the Ga 0.47 In 0.53 As.