Space-charge-limited currents

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We here highlight the importance of reporting mobility values from single-carrier devices with different thicknesses measured at varying device temperature. This is critical in determining how precisely, and what, device and material characteristics can be extracted from SCLC measurements.

Available rom Frontiers in Electronic Materials (open access)

I here show when injection barriers are expected to affect space-charge-limited currents in a single-carrier device, and that it depend on the device temperature, the semiconductor relative permittivity,  effective density if states, and the thickness of the semiconducting film being probed.

Available from the Journal of Computational Electronics

Available on arXiv

An exploration into how space-charge-limited current measurements should be conducted, and how the data should subsequently be analyzed, when probing metal-halide perovskites. An international study between Imperial College London, University of Oxford, University of Sheffield, and New York University.

Available on arXiv

Combining the theories describing ohmic and space-charge-limited conduction, we here derived a general analytical approach to modeling either doped or undoped single-carrier devices.  This work was done in collaboration with Prof. Roderick MacKenzie who is now at Durham University in the United Kingdom.

Available from the Journal of Applied Physics

Available on arXiv

I here present a direct and convenient method for determining the built-in voltage in a single-carrier device directly from the ratio of the forward and reverse currents, without any prior knowledge of the charge-carrier mobility, eliminating the need for complementary measurements.

Available from Physical Review Applied

Here, we show that by allowing the bandlike charge-carrier mobility, trap characteristics, injection barrier heights, and the shunt resistance to vary in a multiple-trapping drift-diffusion model, a numerical fit can be obtained to the entire current density–voltage curve from experimental space-charge-limited current measurements on both symmetric and asymmetric 2,2′,7,7′-tetrakis(N,N-di-4-methoxyphenylamine)-9,9′-spirobifluorene (spiro-OMeTAD) single-carrier devices.

Available from Physical Review Applied

We show that, depending on the thickness of the semiconductor layer and the size of the injection barriers, the Mott–Gurney regime can shrink or disappear, and a meaningful analysis using the Mott–Gurney law will become unachievable, resulting in the mobility being substantially underestimated. General criteria for when to expect deviations from the Mott–Gurney law when used for analysis of intrinsic semiconductors are discussed.

Available from Journal of Physics: Condensed Matter

We discuss the approach of determining the charge-carrier density of a single-carrier device by combining Ohm's law and the Mott–Gurney law, and we subsequently seek to establish a window of conditions where the two methods can be combined to yield reasonable results.

Available from Journal of Physics: Condensed Matter