Morphology and band gap controlled AACVD of CdSe and CdS Se1− thin films using novel single source precursors: Bis(diethyldithio/diselenocarbamato)cadmium(II)

Abstract

a b s t r a c tCadmium selenide (CdSe) and cadmium sulfoselenide (CdS x Se 1 À x ) are important semiconductor materials for photovoltaic and other optoelectronic applications. Highly crystalline thin films of CdSe and CdS x Se 1 À x have been deposited on glass substrates by Aerosol Assisted Chemical Vapour Deposition (AACVD) from bis(diethyldiselenocarbamato)cadmium(II) and a 1:1 and 2:1 mixtures of bis(diethyldiselenocarbamato)cadmium(II) and bis(diethyldithiocarbamato)cadmium(II). Films were characterised by p-XRD, SEM, EDX, Raman spectroscopy, photoluminescence (PL) and UV-vis absorbance spectroscopy. CdSe thin films showed a band gap of 1.73-1.75 eV whereas CdS x Se 1 À x films at 1.90-2.00 eV depending on the sulphur content in the films. PL emission and UV-vis absorbance spectra showed a clear blue shift for CdS x Se 1 À x films compared with CdSe. The band gap of CdSSe can be tuned by controlling the sulphur to selenium ratio in the alloy. The texture of the CdSe thin films changed considerably from randomly orientated to perfect rhombohedral crystallites by increasing the concentration of the precursors in the feed solution.

Sunlight Promotes Fast Release of Hazardous Cadmium from Widely-Used Commercial Cadmium Pigment

“…The XRD spectrum has sharp peaks corresponding to the crystal structure of cadmium sulfoselenide, including 2θ at 24.66°(100), 26.28°( 002), 27.99°(101), 36.34°(102), 43.30°(110), 47.28°(103), 50.38°(200), 51.28°(112), and 52.19°(201). 12,38 ICP-MS measurements suggested the atomic ratio of S:Se of the pigment was 1.9 ± 0.1.…”

“…The observed colloidal stability can be attributed to the small size and negative surface charge of the pigment particles with a ζ-potential of −24.37 ± 1.48 mV (electrophoretic mobility of −1.91 ± 0.12 μm·cm/(V s)), which facilitates their colloidal stability through electrostatic repulsion as suggested by the Derjaguin–Landau–Verwey–Overbeek theory. , The XRD pattern of the commercial pigment is shown in Figure c. The XRD spectrum has sharp peaks corresponding to the crystal structure of cadmium sulfoselenide, including 2θ at 24.66° (100), 26.28° (002), 27.99° (101), 36.34° (102), 43.30° (110), 47.28° (103), 50.38° (200), 51.28° (112), and 52.19° (201). , ICP-MS measurements suggested the atomic ratio of S:Se of the pigment was 1.9 ± 0.1.…”

Composition and Band Gap Controlled AACVD of ZnSe and ZnS<sub>x</sub>Se<sub>1-x</sub> Thin Films Using Novel Single Source Precursors

“…Polycrystalline ZnSxSe 1-x thin films were deposited by co-evaporation of ZnS and ZnSe [36], by low-pressure metal-organic chemical vapour deposition (LP-MOCVD) process from the zinc alkyls dimethylzinc (DMZ) or diethylzinc (DEZ) and H 2 Se and H 2 S [37], and by molecular beam epitaxy (MBE) using radio-frequency (RF) plasma [38]. We have recently reported the deposition of CdSe and CdSSe thin films from molecular precursors by AACVD [39]. Herein we report the deposition of highly crystalline hexagonal ZnSe thin films from bis(diethyldiselenocarbamato)zinc(II) complex and ZnSSe composite from a mixture of bis(diethyldiselenocarbamato)zinc(II) and bis(diethyldithiocarbamato)zinc(II) complexes and their detailed optical and structural characterisation.…”

“…The gas flow rate was controlled at 160 Sccm through a Platon flow gauge. The precursor mist was thermolysed in the hot zone at the surface of glass substrate and resulted in the deposition of thin film as reported previously [39].…”

Low Temperature Scalable Deposition of Copper(I) Thiocyanate Films via Aerosol-Assisted Chemical Vapor Deposition

“…Furthermore, limitations of CuSCN solubility and solution processability are overcome using AACVD, as the technique affords the use of high boiling point solvents, as the necessary aerosol formation depends solely on the surface tension of the solvent. AACVD has previously been used to deposit a variety of semiconductor thin films, including MoS 2 , SnS, CdSe, Cu 2 ZnSnS 4 (CZTS), and more recently CuO x . − Here, we report for the first time the deposition of CuSCN using AACVD.…”