The Zr0.5Hf0.5Ni0.8Pd0.2Sn0.99Sb0.01∕ZrO2 nanocomposites have been prepared by spark plasma sintering technique. The thermoelectric properties were measured in the temperature range of 300–900K. Thermal conductivity for the nanocomposites is considerably reduced, because the nanophase scatters the thermal phonons which transport most of the heat in the ZrNiSn-based alloy. Seebeck coefficient for the nanocomposites is enhanced due to the potential barrier scattering. The dimensionless figure of merit ZT is improved, with ZT≈0.75 at 800K for the samples containing 9vol% ZrO2 nanoinclusions. The results obtained suggest that considerable improvements in the thermoelectric figure of merit may be obtainable by inducing appropriate nanoinclusions into the matrix.

The high temperature thermoelectric performances of Zr0.5Hf0.5Ni0.8Pd0.2Sn0.99Sb0.01 alloy with nanophase inclusions

To enhance efficiencies of quantum dot CdSe/TiO2 based solar cells, understanding of the space charge at the CdSe/TiO2 interface is crucial. In this paper, the presence of a shallow acceptor in the CdSe quantum dots is found by means of a detailed impedance and Mott−Schottky (C−2−ϕ) study. Furthermore, it is clearly shown that this acceptor density decreases strongly with increasing quantum dot size. The presence of these defect states may give rise to Auger recombination in small quantum dots and therewith decrease the efficiency of quantum-dot-sensitized solar cells.

Study of electronic defects in CdSe quantum dots and their involvement in quantum dot solar cells.

The product gas yields for a 30 mTorr C2H2 13.56 MHz glow discharge were measured using mass spectrometry. The volatile products are H2, C4H2, and C6H2. A reaction mechanism has been proposed that accounts quantitatively for the yields of C4H2 and C6H2, and film deposition rate, as a function of discharge power. The product gases C4H2 and C6H2 are depleted at high rates in the plasma by electron collisional dissociation, and by reaction with H atoms and C2H radicals. Under high power conditions suitable for diamondlike carbon deposition it is proposed that the film growth is dominated by the radicals C4H3, C6H3, and C2H. These results are compared with the kinetics of methane rf glow discharges under similar conditions.

Chemical kinetics in low pressure acetylene radio frequency glow discharges

A review of the optical band gap of thin film CdSxTe1−x

Vibrational spectroscopy of compound semiconductor nanocrystals

CdSxTe1-x films (0<x<1) were deposited by simultaneous evaporation of CdS and CdTe powders from a vertical two-zone hot wall evaporation jig onto glass substrates. Electrical conductivity, thermoelectric and optical properties along with microstructural properties were studied in order to derive information on the electron transport processes in the films. Raman scattering was also studied for the films.

https://iopscience.iop.org/article/10.1088/0022-3727/26/4/027/pdf

CdSxTe1-x films: preparation and properties

Schottky diodes of structure Au/nano-CdS/CBD-CdS/SnO 2 were fabricated with the nanocrystalline CdS layer deposited by the high pressure magnetron sputtering technique. The devices were characterized by current-voltage (I-V) anti capacitance-voltage (C-V) measurements. It was observed that the presence of a large amount of surface states might explain the high values of n in the nano-devices. The quantization effects of the active nano-CdS layer in the devices was confirmed from the observed peaks in the plot of conductance versus reverse bias voltage.

Au/CdS Schottky Diode Fabricated with Nanocrystalline CdS Layer

Optical properties of diamond-like transitional films produced by dc plasma deposition of acetylene

Polycrystalline thin films of CdSxSe1−x (0 < x < 08) are prepared by co-evaporating CdS and CdSe from a two-zone evaporation source The films are characterised by measuring optical and electrical properties Information on the microstructures are obtained from XRD and TEM/SEM measurements Raman shifts in the films with composition are also reported Information on the scattering mechanism is derived from the thermoelectric power measurements Grain boundary scattering effects in these films are also studied critically

J. Dutta

Papers

CdSxTe1-x films: preparation and properties

Au/CdS Schottky Diode Fabricated with Nanocrystalline CdS Layer

Optical properties of diamond-like transitional films produced by dc plasma deposition of acetylene

Studies on CdSxSe1−x films prepared by two-zone hot wall technique

Preparation of diamond films by axial magnetron sputtering of vitreous carbon target