Structural, electrical and optical properties of copper selenide thin films deposited by chemical bath deposition technique

Abstract

A low cost chemical bath deposition (CBD) technique has been used for the preparation of Cu 2-x Se thin films on glass substrates. Structural, electrical and optical properties of these films were investigated. X-ray diffraction (XRD) study of the Cu 2-x Se films annealed at 523K suggests a cubic structure with a lattice constant of 5.697Å. Chemical composition was investigated by X-ray photoelectron spectroscopy (XPS). It reveals that absorbed oxygen in the film decreases remarkably on annealing above 423K. The Cu/Se ratio was observed to be the same in as-deposited and annealed films. Both as-deposited and annealed films show very low resistivity in the range of (0.

Plasmonics in heavily-doped semiconductor nanocrystals

“…The relation of the optical gap with the band structure is still controversial, given that only recently more reliable calculations of the band--structure in some of these copper chalcogenides could be carried out. Typically, it is assumed that these materials show an indirect band--gap, mainly based on the square--root energy dependence of the absorption coefficient, as found by Al Mamum et al [42,43] for Cu2--xSe and [44] for Cu2S. However, the magnitude of this coefficient is very large, and comparable to that of direct--gap semiconductors.…”

Recent status of chemical bath deposited metal chalcogenide and metal oxide thin films

“…The average crystal size values are approximately 40 nm for both Cu 3 Se 2 and CuSe thin films. Thin films of cubic Cu 2x Se and tetragonal Cu 3 Se 2 have been prepared by adjusting the bath parameters like pH, temperature and the ratio between copper and selenium ions in the reaction bath [184,185].…”

Structural, morphological, optical and electrical properties of Cu0.87Se thin films coated by electron beam evaporation method

“…From the table, the resistivity, carrier concentration and mobility of the Cu 0.87 Se thin films coated at 300, 400 and 500°C of this work is comparable with the values reported by the earlier workers. Table 3 reveals that non-stoichiometric (Cu 2-x Se) thin films show lower resistivity in the order of 10 -3 -10 -4 X cm, but the stoichiometric copper selenide (CuSe, Cu 2 Se) thin films shows resistivity in the order of 10 1 -10 -1 except CuSe (1.6 9 10 -3 ) thin film prepared by Gosavi RT (70 W ** ) C u 2-x Se 4.75 9 10 -4 2.3 9 10 21 5.5 [26] RT (90 W ** ) C u 2-x Se 3.94 9 10 -4 5.0 9 10 21 2.5 [26] RT (110 W ** ) C u 2-x Se 1.08 9 10 -3 1.3 9 10 21 4.5 [26] PLD RT Cu 1.7 Se -1.4 9 10 22 2.0 [24] CBD RT annealed at 250 Cu 2-x Se 0.5 9 10 -4 1.5 9 10 -4 -- [ 7] 90-95 Cu 2-x Se(x = 0.1) 0.1-2 9 10 -2 -- [ 11] MCBD RT Cu 2 Se *10 -1 -- [ 10] Solution growth RT CuSe 1.6 9 10 -3 -- [ 8] RT CuSe -7-10 9 10 21 0.5-2.5 [9] AACVD 400 450 Cu PLD pulsed laser deposition, CBD chemical bath deposition, MCBD modified chemical bath deposition, AACVD aerosol-assisted chemical vapor deposition, EPD electrophoretic deposition * T s -Substrate temperature ** Sputtering power Structural, morphological, optical and electrical properties of Cu 0.87 Se thin films coated……”

“…Okimura et al [6] prepared Cu 2-x Se-Si junction by conventional vacuum evaporation method and reported that the conversion efficiency of the junction is about 8.3 and 8.8 % for 3-and 2-mm-diameter Cu 2-x Se layer, respectively. Several chemical and physical methods such as chemical bath [2,[7][8][9][10][11], aerosol-assisted chemical vapor deposition [12,13], electroless [14], solgel [15], electrochemical deposition [16], electrophoretic deposition [17], brush electroplate deposition [18], cathodic deposition [19], dip coating [20], spray pyrolysis [21], vacuum co-evaporation [22], vacuum evaporation [6,23], pulsed laser deposition [4,24], selenization [25], magnetron sputtering [26], flash evaporation [27] and reactive evaporation [28] methods have been employed to deposit copper selenide thin films. Ting and Lee [17] prepared Cu 2-x Se nanocrystals by one-pot solution-phase method.…”