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Correlation between Hall Mobility and Optical Mobility in Aluminum‐Doped ZnO Films via Boundary Scatterings and Estimation of Donor Compensation Ratio
Author(s) -
Ghosh Shuvaraj,
Basak Durga
Publication year - 2020
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201900682
Subject(s) - hall effect , scattering , materials science , electron mobility , transmittance , doping , drude model , grain boundary , sputtering , condensed matter physics , optics , analytical chemistry (journal) , thin film , optoelectronics , electrical resistivity and conductivity , chemistry , nanotechnology , microstructure , physics , composite material , quantum mechanics , chromatography
A correlation between the Hall and optical mobility via boundary (BND) scatterings arising from grain as well as surface boundaries in radio frequency (RF) sputtered Al‐doped ZnO (AZO) films done by a comprehensive study on the electrical carrier transport and near infrared optical transmittance properties. AZO films with thicknesses from 100 to 1550 nm are grown by sputtering 1.9 wt% Al 2 O 3 ‐doped ceramic target under identical growth conditions. The Hall measurement shows an increase in the carrier concentration value from 6.93 × 10 20 to 1.1 × 10 21 cm −3 with a mobility value ( μ Hall ) in the range of 4.98–10.3 cm 2 (V s) −1 as the thickness increases. Unprecedentedly, it is shown that the optical mobility value ( μ opt ) calculated using Drude theory is higher than that of the μ Hall up to a film thickness of ≈1000 nm beyond which both the values merges. Though the carrier concentration is higher than 5 × 10 20 cm −3 , BND scattering playing an important role in addition to the in‐grain scattering below a thickness of ≈1000 nm is demonstrated. Considering the BND scattering, donor compensation ratio is calculated and is uniquely found to vary with the film thickness.