K. V. Reich

Metal-insulator transition in films of doped semiconductor nanocrystals

To fully deploy the potential of semiconductor nanocrystal films as low-cost electronic materials, a better understanding of the amount of dopants required to make their conductivity metallic is needed. In bulk semiconductors, the critical concentration of electrons at the metal-insulator transition is described by the Mott criterion. Here, we theoretically derive the critical concentration nc for films of heavily doped nanocrystals devoid of ligands at their surface and in direct contact with each other. In the accompanying experiments, we investigate the conduction mechanism in films of phosphorus-doped, ligand-free silicon nanocrystals. At the largest electron concentration achieved in our samples, which is half the predicted nc, we find that the localization length of hopping electrons is close to three times the nanocrystals diameter, indicating that the film approaches the metal-insulator transition.

Accumulation, inversion, and depletion layers in SrTiO3

We study potential and electron density depth profiles in accumulation, inversion, and depletion layers in crystals with a large and nonlinear dielectric response such as

Exciton Transfer in Array of Epitaxially Connected Nanocrystals.

{\mathrm{SrTiO}}_{3}

Dielectric constant and charging energy in array of touching nanocrystals

. We describe the lattice dielectric response using the Landau-Ginzburg free energy expansion. In accumulation and inversion layers we arrive at new nonlinear dependencies of the width

Disorder from the Bulk Ionic Liquid in Electric Double Layer Transistors

d

Surface roughness scattering in multisubband accumulation layers

of the electron gas on an applied electric field

Universality of electron mobility in LaAlO3/SrTiO3 and bulk SrTiO3

{D}_{0}

Anomalous conductivity, Hall factor, magnetoresistance, and thermopower of accumulation layer in SrTiO3

. Particularly important is the predicted electron density profile of accumulation layers (including the

Collapse of electrons to a donor cluster in SrTiO

{\mathrm{LaAlO}}_{3}/{\mathrm{SrTiO}}_{3}

_3

interface)