Cd(2+) causes deep traps on the surface of CdTe quantum dots (QDs) often leading to a long response time for a photodetector. Poly(3-hexylthiophene) (P3HT) can be used to selectively passivate the Cd(2+) -related deep traps by forming a Cd-S bond, while maintaining the shallow traps. By tailoring the trap depth of the CdTe QDs, a high gain, fast response, and low noise P3HT:CdTe nanocomposite p...

Charge separation and diffusion in type II multilayered structures of CdTe and CdSe nanocrystals with a polymer spacer are unambiguously proven by surface photovoltage spectroscopy. Holes accumulate in CdTe nanocrystal layers, and the electrons in CdSe nanocrystal layers. An increase of thickness of the polymer spacer strongly decreases the charge separation efficiency. Surface photovoltage tra...

Differential pulse voltammetry (DPV) of TOPO-capped CdTe nanoparticles (NPs) in dichloromethane and a mixture of benzene and acetonitrile showed two anodic and one cathodic peaks of the NPs themselves and an additional anodic peak resulting from the oxidation of reduced NPs. The electrochemical band gap (∼2.1 eV) between the first anodic and cathodic DPV peaks was close to the value (2 eV) obta...

Eta-solar cells were fabricated and analysed, these are thin film solar cells with an extremely thin absorber (here p-type CdTe) and a nanoor microstructured n-type TiO2 layer. The illuminated I-V curves are S-shaped. Quantum efficiency curves were measured under forward and reverse voltage bias, with and without light bias, and with varying front and back side illumination. These characteristi...

We are developing a Compton telescope based on high resolution Si and CdTe imaging devices in order to obtain a high sensitivity astrophysical observation in sub-MeV gamma-ray region. In this paper, recent results from the prototype Si/CdTe semiconductor Compton telescope are reported. The Compton telescope consists of a double-sided Si strip detector (DSSD) and CdTe pixel detectors, combined w...

The most notable obstacle of brain cancer diagnosis is the inability of delivering imaging agents across the blood-brain barrier (BBB). Recently, quantum dots (QDs) has been demonstrated as an ideal image agent for brain imaging due to their ultra-small size for crossing BBB. The plolyamidoamine dendrimers modified CdTe/CdS core/shell near-infrared (NIR) region QDs was successfully synthesized ...

High density compound materials (CdTe, GaAs, HgI2) are currently evaluated as direct photon conversion sensors for applications in X-ray imaging. A new front-end stage has been designed with the aim to be implemented as readout chain in a luggage inspection system based on a linear array of CdTe sensors. Both types of electron or hole collecting CdTe sensors will be evaluated. Each detecting el...

We have developed a large CdTe pixel detector with dimensions of 23.7 × 13.0 mm and a pixel size of 448 × 448 μm. The detector is based on recent technologies of an uniform CdTe single crystal, a two-dimensional ASIC, and stud bump-bonding to connect pixel electrodes on the CdTe surface to the ASIC. Good spectra are obtained from 1051 pixels out of total 1056 pixels. When we operate the detecto...

AMPTEK INC. 14 DeAngelo Drive, Bedford, MA 01730-2204 U.S.A. APPLICATIONS • X-Ray Fluorescence • Thin-film Analysis • RoHS/WEEE Analysis • Teaching and Research • Art and Archaeology • Process Control • X-ray Tube Characterization FEATURES • Fundamental parameters (FP) • Analysis with or without standards • General bulk and thin-film analysis • Analyze up to 40 elements • Supports all Amptek de...