Structure and electrical resistance of the passivating ZnSe layer on Ge

In this article, we have considered the p-i-n Ge photodetector with ZnSe passivating layer. Passivation layer needs to be protected photodetector from dust, rain drops and other external influences. However, this passivation layer can cause errors in photodetector image. When creating a passivating ZnSe layer on Ge, which is used in p-i-n Ge photodetectors, we found two additional phases GeSe and GeSe2 that do not contradict with their state diagram. The above phases can have an essential effect on performances of the passivating layer. Therefore, to study the electrical resistance of this layer, we prepared model samples of layers containing the GeSe and GeSe2 with the thickness 0.5…1.8 µm and area 1 cm2. To measure the electrical resistance of these layers, we used elastic contacts. The performed measurements have shown that Se layers on Ge have an intermediate resistance between that of ZnSe on Ge and pure Ge, and, therefore, the effect of additional phases practically does not worsen the passivating properties of the ZnSe layer on Ge.

Structure and Electrical Resistance of the Passivating ZnSe Layer on Ge

When creating a passivating ZnSe layer on Ge, which is used in p-i-n Ge photodetector, we found two additional phases GeSe and GeSe2 that does not contradict with their state diagram. The above phases can have an essential effect on performances of the passivating layer. Therefore, to study the electrical resistance of this layer we prepared model samples of layers containing the GeSe and GeSe2 with the thickness 0.5…1.8 µm and area 1 cm2. To measure the electrical resistance of these layers, we used elastic contacts. The performed measurements have shown that Se layers on Ge have an intermediate resistance between that of ZnSe on Ge and pure Ge, and, therefore, the effect of additional phases practically does not worsen the passivating properties of the ZnSe layer on Ge.

Design and Characterization of a Sharp GaAs/Zn(Mn)Se Heterovalent Interface: A Sub-Nanometer Scale View

The distribution of magnetic impurities (Mn) across a GaAs/Zn(Mn)Se heterovalent interface is investigated combining three experimental techniques: Cross-Section Scanning Tunnel Microscopy (X-STM), Atom Probe Tomography (APT), and Secondary Ions Mass Spectroscopy (SIMS). This unique combination allowed us to probe the Mn distribution with excellent sensitivity and sub-nanometer resolution. Our results show that the diffusion of Mn impurities in GaAs is strongly suppressed; conversely, Mn atoms are subject to a substantial redistribution in the ZnSe layer, which is affected by the growth conditions and the presence of an annealing step. These results show that it is possible to fabricate a sharp interface between a magnetic semiconductor (Zn(Mn)Se) and high quality GaAs, with low dopant concentration and good optical properties.

Effect of Heat Treatment on Electrodeposited ZnSe on Vertically Aligned ZnO Nanorods for Photoelectrochemical Cell

Following successful growth of zinc oxide (ZnO) nanorods, a layer of zinc selenide (ZnSe) was electrodeposited onto the nanorods to further enhance its conversion efficiency in the photoelectrochemical (PEC) cell. The electrodeposited ZnSe layer onto the ZnO nanorods was subjected to heat treatment at 200, 250 and 300°C. The prepared films were characterized by X-ray diffractometry (XRD), field emission scanning electron microscopy (FESEM), and ultraviolet-visible spectroscopy (UV-Vis) to investigate the structural, morphological and compositional characteristics. Additionally, PEC conversion generated by the prepared thin films were tested with photocurrent measurements under calibrated visible illumination from a halogen lamp. Based on FESEM analysis, the thickness of ZnO thin film increased with temperature. However, the diameters of the ZnO nanorods were found to be in a decreasing trend upon heat treatment at higher temperature. The electrodeposited ZnSe layer at the potential of -0.7 V for 60 seconds (calcined at 200°C) possessed crystallite size of 20.1 nm. According to UV-Vis analysis, band gap energy measured was 2.8 eV, which is very close to standard ZnSe band gap value (2.7 eV). Additional layer of ZnSe electrodeposited enhanced thin film performance in terms of current density as much as 37.4% while having high photocurrent density of 0.2671 mAcm-2.

Organic photovoltaic cells utilising ZnO electron extraction layers produced through thermal conversion of ZnSe

A thin ZnSe layer was deposited by thermal evaporation in vacuum and thermally annealed in air to provide an efficient ZnO electron extraction layer for an inverted small molecule organic photovoltaic cell.

EFFECT OF Mn IONS ON SPIN RELAXATION AND LIFE-TIME OF e-h COMPLEXES IN CdSe/ZnSe/ZnMnSe QUANTUM DOTS

Photoluminescence measurements on individual CdSe / ZnSe / ZnMnSe quantum dots in a magnetic field up to 11 T both parallel and perpendicular to the sample growth plane at 1.6 K reveal a qualitative difference between samples with different strength of the sp-d exchange interaction controlled by means of varying the thickness of the nonmagnetic ZnSe layer. The observed difference is related with the dependence of the non-radiative Mn assisted recombination and the spin relaxation on magnetic field and the strength of the exchange interaction.