Magnetic order in the two-dimensional randomly mixed ferromagnet-antiferromagnet Rb2Cu1-xCoxF4

Elucidation of homojunction formation in CuInS2 with impedance spectroscopy

Type transformation in CuInSe2 and CuInS2 solar cells is an important issue with far reaching consequences. In the present study, the presence of a p-n homojunction inside CuInS2 in a TiO2/CuInS2 device is revealed with a detailed impedance spectroscopy and capacitance study. A n-type CuInS2 film with a thickness of 40?nm is found at the TiO2 (n...

Activated dynamics in the two-dimensional Ising spin-glass Rb2Cu1-xCo xF4

Tip-based chemical vapor deposition with a scanning nano-heater

In this preliminary effort, a moving nano-heater directs a chemical vapor deposition reaction (nano-CVD) demonstrating a tip-based nanofabrication (TBN) method. Localized nano-CVD of copper (Cu) and copper oxide (CuO) on a silicon (Si) and silicon oxide (SiO2) substrate from gasses, namely sublimated copper acetylacetonate (Cu(acac)2), argon (Ar...

Static and dynamic properties of the two-dimensional Ising spin glass Rb2Cu1-xCo xF4

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...

Deep-level transient spectroscopy of TiO2/CuInS2 heterojunctions

Deep-level transient spectroscopy (DLTS) has been used to measure the concentration and energy position of deep electronic states in CuInS2. Flat TiO2?CuInS2 heterojunctions as well as TiO2-CuInS2 nanocomposites have been investigated. Subband-gap electronic states in CuInS2 films are mostly due to antisite point defects and vacancies....

Time-of-flight studies on TiO2/CuInS2 heterojunctions

Time-of-Flight (TOF) measurements have been performed on n-type TiO2/p-type CuInS2 heterojunctions. The TiO2 film thickness has been varied between 200 and 400 nm, while the CuInS2 film thickness has been fixed at 500 nm. The TOF response can be accurately modeled, if the potential drop across the p-n heterojunction with a large density of...

Rb2Cu1-xCoxF4, a two-dimensional Ising spin glass

Ambipolar Cu- and Fe-phthalocyanine single-crystal field-effect transistors

We report the observation of ambipolar transport in field-effect transistors fabricated on single crystals of copper- and iron-phthalocyanine, using gold as a high work-function metal for the fabrication of source and drain electrodes. In these devices, the room-temperature mobility of holes reaches 0.3?cm2/V?s in both materials. The highest...

Tuning the charge density wave and superconductivity in CuxTaS2

We report the characterization of layered 2H-type CuxTaS2 for 0?x?0.12. The charge density wave (CDW), at 70 K for TaS2, is destabilized with Cu doping. The sub-1 K superconducting transition in undoped 2H-TaS2 jumps quickly to 2.5 K at low x, increases to 4.5 K at the optimal composition Cu0.04TaS2, and then decreases at higher x. The...

Efficiency enhancement calculations of state-of-the-art solar cells by luminescent layers with spectral shifting, quantum cutting, and quantum tripling function

Solar cells of which the efficiency is not limited by the Shockley-Queisser limit can be obtained by integrating a luminescent spectral conversion layer into the cell structure. We have calculated the maximum efficiency of state-of-the-art c-Si, pc-Si, a-Si, CdTe, GaAs, CIS, CIGS, CGS, GaSb, and Ge solar cells with and without an integrated...

Static critical behavior of the two-dimensional Ising spin glass Rb2Cu1-xCo xF4