Role of neutral impurity scattering in the analysis of Hall data from ZnO

Zinc oxide is a wide band-gap semiconductor with bright UV emission. To determine donor and acceptor concentrations affecting electrical properties in n-type ZnO crystals, the relaxation time approximation has been used to analyze mobility ($\mu )$ and carrier concentration data measured from 80 to 400 K. Five scattering mechanisms are included: polar-optical-phonon, piezoelectric potential, deformation potential, ionized impurity, and neutral impurity (NI) scattering. The NI scattering is often ignored but plays an important role in limiting the total $\mu $. By including NI scattering, the experimental deformation potential E$_{1}$ = 3.8 eV can be used. Temperature dependences of the intrinsic Hall r factor and intrinsic $\mu $ are determined. At 300 K, ``pure'' ZnO has an electron $\mu $ of about 210 cm$^{2}$/Vs. Analysis of Hall data from commercial hydrothermally and CVT-grown n-type ZnO crystals is presented. Donor and acceptor concentrations from Hall data are compared with those estimated using infrared absorption and EPR data. Intrinsic hole mobility in p-type ZnO is also discussed. This work was supported by NSF Grant No. DMR-0508140.