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The behavior of the trapping times of minority carriers in In-doped CdTe films because of annealing and hydrogenation was examined through photoconductivity (PC) measurements on as-grown, annealed, hydrogenated, and hydrogenated and annealed In-doped CdTe epitaxial films grown on p-CdTe (211) substrates by molecular beam epitaxy. Results of the PC decay curve revealed a slow component with a time constant of a few milliseconds and this behavior was related to the presence of deep travel levels corresponding to minority carriers. The trapping times of the minority carriers were substantially decreased by the hydrogenation treatment.

The p-type GaN epilayers are prepared by metalorganic chemical vapor deposition and subsequently implanted with Fe(super +) ions. The study confirms that the photoluminescence peak at 2.5 eV is a donor-Fe acceptor transition and the photoluminescence peak around 3.1 eV is a conduction band-Fe acceptor transition.

A new study investigates the effect of surface passivation on the photoelectrical and optical properties of undoped p-CdTe(100) by (NH4)2Sx treatment.

In this paper, we report a study on the optical and electrical properties of pure cotton fibers from chemically surface and morphology modified and coated with poly [2-methoxy-5-(2-ethylhexyloxy)-1, 4-phenylenevinylene] (MEH-PPV) polymer samples by the dip-coating method. The treated and coated fibers properties were characterized by using scanning electron microscopy (SEM), photoluminescence, and I-V characteristics. The performance of fibers with the MEH-PPV polymer as a coating component was investigated and an excellent white-light emission which consists of blue-, green-, and red-light-emitting bands was demonstrated. I-V characteristics of the sandwich-type devices consisting of successive layers of ITO-PEDOT-PSS- CF/MEH-PPV-Ag show that upon light illumination the current increases in both the forward and reverse bias conditions which suggest that the photoresponse parameters for the heterojunction are better than the composite alone. [ABSTRACT FROM AUTHOR]

Undoped and nitrogen doped ZnO films were deposited on Si substrates by ultrasonic spray pyrolysis at ambient atmosphere. The p type of conductivity for the nitrogen doped ZnO films has been observed. The concentration of free holes in ZnO films has been found to depend strongly on the resistivity of Si substrate. With decreasing of the substrate resistivity the concentration of free holes in ZnO films increases. The hole concentration of 1.1×1018 cm-3 and the hole mobility of 24 cm2 V-1 s-1 were observed in the ZnO films grown on the Si substrates with the resistivity of 0.001 Ω cm. [ABSTRACT FROM AUTHOR]

The study of diluted magnetic semiconductor based on GaN was performed employing a variety of various measurement techniques. p-type GaN epilayers were prepared by metalorganic chemical vapor deposition and were subsequently implanted with Mn[sup +] ions. The properties of Mn[sup +] ion-implanted GaN epilayers were investigated with optical and magnetic measurements. The results of photoluminescence (PL) measurement show that optical transitions related to Mn apparently appear at 2.5 and around 3.0 eV. It is confirmed that the PL peak at 2.5 eV is a donor-Mn acceptor transition and the PL peak around 3.0 eV is a conduction band-Mn acceptor transition. Ferromagnetic hysteresis loop was observed, and the temperature dependent-magnetization displayed a ferromagnetic behavior persisting up to ∼270 K. [ABSTRACT FROM AUTHOR]

Investigates the effects of the band-tail states on the exciton lines in unintentionally doped and Mg-doped GaN epilayers grown on sapphire substrates with the use of plasma-assisted molecular beam epitaxy. Relationship between the radiative recombinations of the carriers and the band-tail states.

A variety of various measurement techniques were employed to perform the study of diluted magnetic semiconductor based on GaN. The properties of Mn(super +1) ion-implanted GaN epilayers were investigated with optical and magnetic measurements.

The thermal diffusivity measurements have been used to study the magnetic phase transition in Zn0.95Mn0.05O doped by nitrogen. The critical parameters of the ferromagnetic-paramagnetic transition have been obtained through the analysis of the inverse of the thermal diffusivity near the Curie temperature. Taking into account that the inverse of the thermal diffusivity has the same critical behavior as the specific heat, the critical exponent α has been determined. The results are consistent with the three-dimensional Heisenberg model for the magnetic phase transition. [ABSTRACT FROM AUTHOR]

p-type GaN epilayers were prepared by metalorganic chemical vapor deposition and subsequently implanted with Fe[sup +] ions. The properties of Fe[sup +] implanted GaN epilayers were investigated by various measurements. The results of photoluminescence measurement show that optical transitions related to Fe appear at 2.5 eV and around 3.1 eV. It was confirmed that the photoluminescence peak at 2.5 eV is a donor-Fe acceptor transition and the photoluminescence peak around 3.1 eV is a conduction band-Fe acceptor transition. Apparent ferromagnetic hysteresis loops measured at 10 and 300 K were observed, and the temperature-dependent magnetization displayed a ferromagnetic behavior persisting above 350 K. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]