Influence of Pulse Width on CdS Film Prepared by YAG Laser Ablation

Abstract

CdS films were deposited on glass substrates using two kinds of YAG lasers: one with a long pulse width of τ=100 µs and one with a short pulse width of τ=15 ns. Scanning electron microscopy observation and X-ray diffraction patterns showed that the film formed by the long pulse laser with a low energy density has a smooth surface and highly oriented texture. Resistivity is distributed in a wide range: 100-2000 Ω·cm and 10-100 Ω·cm for the films formed by long and short pulse lasers, respectively. Measurement of optical transmission spectra suggests the existence of an impurity level in the low resistivity film. Streak image of the plume obtained using an image converter camera showed that the average velocity of ablated luminous particles is about 5×104 cm/s for long pulse laser ablation and (3-9)×105 cm/s for the short one.

Laser ablation and deposition of wide bandgap semiconductors: plasma and nanostructure of deposits diagnosis

“…The velocity for both materials is 9 x 10 3 m/s. This value agrees well with reported velocities of atomic species generated in UV and IR ablation plumes of semiconducting materials (Ezumi and Keitoku 1993, Klini et al 2005, Sanz et al 2009). …”

“…In particular, PLD serves to produce nanostructured CdS (Ezumi and Keitoku 1993, Ullrich et al 2003, Perna et al 2004, Mahdavi et al 2005, VigilGalan et al 2006, Acharya et al 2007, El Deeb 2007, Tong et al 2006, Tong et al 2007, Tong et al 2008 and ZnS films (McLaughlin et al 1993, Yoo et al 2001, Hillie et al 2001, Yano et al 2003, Cafeing et al 2010, Chung et al 2010, both in nanosecond (ns) and femtosecond (fs) regimes.…”

“…For these materials efforts have been addressed to study the dependence of the deposits on pulse laser duration, fluence and wavelength (see for example Ullrich et al 2003 and references therein) and some works have concentrated on establishing relations between the composition and dynamics of the plume and the structure and morphology of the deposited films (Ezumi andKeitoku. 1993, Sanz et al 2011).…”

Employment of Pulsed-Laser Deposition for Optoelectronic Device Fabrication

“…Due to the use of relatively short laser pulses (ns pulse duration and faster), PLD can be apostrophized as "explosive material flash". The point is that the film formation is over before the material decomposes owing to the supersonic velocity (10 4 -10 5 m/s) of the plume particles (Ezumi & Keitoku, 1993). For the distance of 6 cm, the deposition takes place within 600 ns-6 μs.…”

Optical properties of Zn x Cd 1- x S mixed crystal thin film produced by PLD

“…Using the laser target consisted with the mixed powder, various mixed crystal can be obtained with desirable composition. Moreover, the thin film of high melting point material with no impurity can be obtained using the high-power laser [10]. If the ZnCdiS thin film which have good crystallinity will be obtained by the PLD, it is applicable to optical devices used from visible to UV region, for examples, LED, LD, photo detector, light switch or optical filter.…”