Disorder Originated Unusual Mobility in Crystalline InGaZnO4

Using calculations from first principles, the site disorder between Ga and Zn of crystalline InGaZnO
₄
is shown to play key roles in its unique transport properties. The analysis based on Density Functional Theory reveals that the various types of scattering centers stem from the charge imbalance between the ordered and disordered structures are the prime factor in explaining the carrier mobility of the crystalline InGaZnO
₄
. The phonon dispersion of crystalline InGaZnO
₄
is also examined to include the influence of scattering by polar optical phonons. The Hall mobility calculation based on Boltzmann transport equation under relaxation time approximation shows that the site disorders of 2.5×10
²¹
cm
^-3
~5×10
²¹
cm
^-3
can dominate the transport character. The comparisons with experimental data demonstrate excellent agreement in the wide ranges of temperature (100~300 K) and doping densities (10
¹⁶
~10
²⁰
cm
^-3
). Our results provide a critical measure to estimate a device performance utilizing quasi-crystalline InGaZnO
₄
along with a deeper understanding of its peculiar transport characters.