Raman Scattering from ZnSe Nanolayers

Abstract

A series of ZnSe single layers having thickness between 30 nm and 1 µm was deposited on c-Si and glass substrates at room substrate temperature. Thermal evaporation of ZnSe powder in high vacuum has been applied. Moreover, SiO x /ZnSe periodic multilayers prepared by the same deposition technique and having ZnSe layer thickness of 2 and 4 nm have been studied. Raman spectra were measured at 295 K, using the 442 nm line of a He-Cd laser as well as different lines of the Ar + or Ar + /Kr + lasers. The observed Raman features have been related to multiple optical phonon (1LO to 4LO) light scattering and connected with the existence of randomly oriented crystalline ZnSe grains in both ZnSe single layers and ZnSe layers of the multilayers. Relatively large line width (≈ 15 cm −1 ) of the 1LO band has been observed and related to lattice distortion in the crystalline grains and existence of amorphous phase in the layers thinner than 100 nm. The Raman spectra measured on both ZnSe single layers and SiO x /ZnSe multilayers using the 488 nm line with a gradually increased laser beam power indicate an increased crystallinity at high irradiation levels.

Study on Raman spectra of zinc selenide nanopowders synthesized by hydrothermal method

“…3, it is obvious that the peak at about 206 cm −1 in (a) is broader than that in (b) and (c) and it is difficult to resolve, however the peak at about 252 cm −1 in (a) is the strongest in the peaks at about 252 cm −1 of Fig. 3, which the similar results were observed in ZnSe film by Nesheva et al [14]. We think they are related to the structures and size of the ZnSe particles.…”

Tune-Ability of Physical Properties of Nanocrystalline Cu x Zn1−x Se Thin Films with Copper Concentration

“…29 The spectrum reveals two characteristic longitudinal optical (LO) phonon bands ($252, 497) cm À1 associated with the cubic structure of ZnSe thin films because the excitation energy is well above the optical band-gap of the material. 30 These observed phonon modes of ZnSe thin films are in good agreement with those reported in the literature. 31,32 A phonon band at 280 cm À1 appearing as either a kink at the shoulder or as a separate peak on the higher-frequency side of the LO phonon is the system peak, as it lies within the width of this phonon and could not be assigned as the sample peak.…”

Effect of thermal annealing on the physical properties of Zn1−x Cu x Se thin films deposited by close spaced sublimation technique

“…Both the as deposited and the annealed samples have the same vibrational modes however another mode was observed for 400 • C annealed samples at 750 cm −1 . This observed mode is associated to ZnSe [20] . In addition, the peak intensity of Raman Spectra s increases and become sharper with annealing which is due to improvement in the crystalline structure with the grain growth.…”