Charge transport in amorphous InGaZnO thin-film transistors
2012 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 86, no 15, 155319Article in journal (Refereed) Published
We investigate the mechanism of charge transport in indium gallium zinc oxide (a-IGZO), an amorphous metal-oxide semiconductor. We measured the field-effect mobility and the Seebeck coefficient (S = Delta V/Delta T) of a-IGZO in thin-film transistors as a function of charge-carrier density for different temperatures. Using these transistors, we further employed a scanning Kelvin probe-based technique to determine the density of states of a-IGZO that is used as the basis for the modeling. After comparing two commonly used models, the band transport percolation model and a mobility edge model, we find that both cannot describe the full properties of the charge transport in the a-IGZO semiconductor. We, therefore, propose a model that extends the mobility edge model to allow for variable range hopping below the mobility edge. The extended mobility edge model gives a superior description of the experimental results. We show that the charge transport is dominated by variable range hopping below, rather than by bandlike transport above the mobility edge.
Place, publisher, year, edition, pages
American Physical Society , 2012. Vol. 86, no 15, 155319
IdentifiersURN: urn:nbn:se:liu:diva-118137DOI: 10.1103/PhysRevB.86.155319ISI: 000310259900006OAI: oai:DiVA.org:liu-118137DiVA: diva2:813748
Funding Agencies|Dutch Technology Foundation STW, applied science division of NWO; Ministry of Economic Affairs ; European Community [246334-2]2015-05-252015-05-222015-06-04