Imaging of charge trapping in distorted carbon nanotubes by x-ray excited scanning probe microscopy

We have observed the distribution of electron trapping centers on distorted carbon nanotubes (CNTs) by a unique x-ray analysis technique that has both elemental and spatial selectivities. This technique involves the use of scanning probe microscopy (SPM) under synchrotron radiation excitation of the inner shell of carbon. The probe detects the...

Lanthanide 4f-level location in lanthanide doped and cerium-lanthanide codoped NaLaF4 by photo- and thermoluminescence

Photo- and thermoluminescence (TL) spectra of NaLaF4:Ln3+ (Ln = Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm) and NaLaF4:Ce3+, Ln3+ (Ln = Nd,Sm,Ho,Er,Tm) are presented and used together with the empirical Dorenbos model in order to establish the 4f energy level positions of all tri- and divalent lanthanide ions doped in NaLaF4. The information will be...

Spin droplets in confined quantum Hall systems

Two-dimensional semiconductor quantum dots are studied in the filling-factor range 2<v<3. We find both theoretical and experimental evidence of a collective many-body phenomenon, where a fraction of the trapped electrons form an incompressible spin droplet on the highest occupied Landau level. The phenomenon occurs only when the number of...

A time-resolved microwave conductivity study of the optoelectronic processes in TiO2?In2S3?CuInS2 heterojunctions

Photoinduced interfacial charge carrier generation, separation, trapping, and recombination in TiO2?In2S3?CuInS2 cells have been studied with time-resolved microwave conductivity (TRMC). Single layer, double layer, and complete triple layer configurations have been studied. Selective electronic excitation in one of the components is accomplished...

Luminescence quenching by photoionization and electron transport in a LaAlO3:Ce3+ crystal

A combined photoconductivity, absorption, and thermoluminescence study was performed to understand the absence of luminescence from Ce3+ in LaAlO3:Ce3+. It is demonstrated that the absence of luminescence is the result of Ce3+ ionization from the 5d excited states, which are all located in the conduction band. Ce3+ ionization is accompanied by...