Annealing Effects on Impurity Band Conduction of ZnSnAs₂Epitaxial Films

Epitaxial growth and characterization of Cr-doped ZnSnAs2thin films on InP substrates

“…4, compared with the reference sample, Cr1 showed reduced carrier concentration, which is likely due to the reduction of hole-producing Zn vacancies. 39,40) Moreover, compared with Cr1, Cr2 also showed a reduced hole carrier concentration, which is contrary to what we expected when Cr substitutes on Sn sites. However, this contradiction is easily resolved by recognizing that, at the same time, incorporation of Cr atoms also reduced hole-producing Zn vacancies, which seems to be the dominant factor for Cr1.…”

Composites based on self-assembled MnAs ferromagnet nanoclusters embedded in ZnSnAs2 semiconductor

“…7b are not in line with the above supposition, too. On the other hand, it has been shown that already in the pure as-grown ZnSnAs 2 film the observed dependences of µ(T) and p(T) satisfy reasonably those of the two-band conduction mechanism, taking into account the holes in the valence band and in the acceptor band [26]. It is worth mentioning the two-band conduction, observed in the II-V semiconductor CdSb [27] and in the III-V based In 1-x Mn x Sb [28], permitting a detailed quantitative explanation of the resistivity and the Hall effect data in strong magnetic fields.…”

“…All our samples are p-type semiconductors.The Hall concentration of holes in the nanocomposite ZnSnAs 2 + MnAs samples is much higher than in the ZnSnAs 2 sample. However, the acceptor concentration N A in all samples exceeds that of the metal-insulator transition (MIT), N C , given by the Mott criterion N C 1/2 a B ≈ 0.25[24,25],where a B = ħ 2 ε 0 /(me 2 ) is the Bohr radius, ε 0 = 12 is the dielectric permittivity far from the MIT and m = 0.39 m 0 is the hole effective mass (here m 0 is the free electron mass)[26]. Indeed, using the data above, we obtain a B = 16.3 Å and N C ≈ 3.6×10 18 cm −3 .…”

Growth and characterization of Ga doped ZnSnAs2 thin films on InP substrates

“…At this regime, the conduction is dominated by holes in the impurity acceptor band. According to prediction by Asubar [10], if an impurity concentration was ~2.03×10 18 cm -3 , the impurity band conduction in ZnSnAs 2 system would be occurred. This carrier concentration corresponds to the R o of ~3.08 cm 3 /C.…”

“…As a result, we inferred that for the as-grown sample and the Ga 8.7% doped sample, impurity band conduction would be most likely present, while for the Ga 20.9% doped sample, the impurity concentration is too low to form the well conducting impurity band. In the following discussion, we analyze only the measured temperature dependence of the R o and the ρ of the Ga 8.7% doped sample within the framework of the impurity band model, since analytic details of as-grown sample have been published elsewhere [10]. …”