Hole Transport in p-Type ZnO

A two-band model involving the A- and B-valence bands was adopted to analyze the temperature dependent Hall effect measured on N-doped \textit{p}-type ZnO. The hole transport characteristics (mobilities, and effective Hall factor) are calculated using the ``relaxation time approximation'' as a function of temperature. It is shown that the lattice scattering by the acoustic deformation potential is dominant. In the calculation of the scattering rate for ionized impurity mechanism, the activation energy of 100 or 170 meV is used at different compensation ratios between donor and acceptor concentrations. The theoretical Hall mobility at acceptor concentration of $7 \times 10^{18}$ cm$^3$ is about 70 cm$^2$V$^{-1}$s$^{-1}$ with the activation energy of 100 meV and the compensation ratio of 0.8 at 300 K. We also found that the compensation ratios conspicuously affected the Hall mobilities.Comment: 5page, 5 figures, accepted for publication in Jpn. J. Appl. Phy

Temperature dependent magnetotransport around ν\nu= 1/2 in ZnO heterostructures

The sequence of prominent fractional quantum Hall states up to $\nu$=5/11 around $\nu$=1/2 in a high mobility two-dimensional electron system confined at oxide heterointerface (ZnO) is analyzed in terms of the composite fermion model. The temperature dependence of \Rxx oscillations around $\nu$=1/2 yields an estimation of the composite fermion effective mass, which increases linearly with the magnetic field. This mass is of similar value to an enhanced electron effective mass, which in itself arises from strong electron interaction. The energy gaps of fractional states and the temperature dependence of \Rxx at $\nu$=1/2 point to large residual interactions between composite fermions.Comment: 5 pages, 4 Figure

Electron scattering times in ZnO based polar heterostructures

The remarkable historic advances experienced in condensed matter physics have been enabled through the continued exploration and proliferation of increasingly richer and cleaner material systems. In this work, we report on the scattering times of charge carriers confined in state-of-the-art MgZnO/ZnO heterostructures displaying electron mobilities in excess of 10⁶ cm²/V s. Through an examination of low field quantum oscillations, we obtain the effective mass of charge carriers, along with the transport and quantum scattering times. These times compare favorably with high mobility AlGaAs/GaAs heterostructures, suggesting the quality of MgZnO/ZnO heterostructures now rivals that of traditional semiconductors

Temperature-Dependent Magnetotransport around ν=1/2 in ZnO Heterostructures

The sequence of prominent fractional quantum Hall states up to ν = 5/11 around ν = 1/2 in a high-mobility two-dimensional electron system confined at oxide heterointerface (ZnO) is analyzed in terms of the composite fermion model. The temperature dependence of R_(xx) oscillations around ν = 1/2 yields an estimation of the composite fermion effective mass, which increases linearly with the magnetic field. This mass is of similar value to an enhanced electron effective mass, which in itself arises from strong electron interaction. The energy gaps of fractional states and the temperature dependence of R_(xx) at ν = 1/2 point to large residual interactions between composite fermions

Temperature-Dependent Magnetotransport around ν=1/2 in ZnO Heterostructures

The sequence of prominent fractional quantum Hall states up to ν = 5/11 around ν = 1/2 in a high-mobility two-dimensional electron system confined at oxide heterointerface (ZnO) is analyzed in terms of the composite fermion model. The temperature dependence of R_(xx) oscillations around ν = 1/2 yields an estimation of the composite fermion effective mass, which increases linearly with the magnetic field. This mass is of similar value to an enhanced electron effective mass, which in itself arises from strong electron interaction. The energy gaps of fractional states and the temperature dependence of R_(xx) at ν = 1/2 point to large residual interactions between composite fermions