Preparation and characterization of Cu(In1−xGax)3Se5 thin films

Abstract

Polycrystalline Cu(In1−xGax)3Se5 thin films were prepared by four source evaporation with controlling and shielding of the molecular beams from elemental sources. Ga content x, can be controlled by deposition times of CuIn3Se5 and CuGa3Se5 layers, which form Cu(In1−xGax)3Se5 films through the interdiffusion. X-ray diffraction analyses showed that the films with x≲0.5 have an ordered vacancy chalcopyrite and the films with x≳0.5 have a zinc blende structure. The optical band gap of the films linearly increased from 1.23 eV (x=0) to 1.85 eV (x=1) with increasing Ga content. The conductivity of the films was about 10−6/Ω cm and about 10−7/Ω cm under and above x=0.3, respectively.

Identification of Optical Transitions by Spectroscopic Ellipsometry (SE) on CuIn<sub>3</sub>Se<sub>5</sub> Bulk Compounds

“…In these cases, the gap value is given by an approximate value which was found by taking the abscissa of each curve at PC max /2 [17]. The gap value at room temperature is 1.22 eV, which match those found by Photoluminescence and in literature [18]. …”

Modeling the optical constants of Cu2In4Se7 and CuGa3Se5 crystals

“…Our obtained values of E g = 1.125 for I247 and 1.85 eV for and G35 at room temperature ͑Table II͒ are in a reasonable agreement with those obtained from the optical measurements. [4][5][6][7][8][9][10] The variation in the reported values of the band gap of OVC can be attributed to the compositional change. The chalcopyrites and OVCs usually exhibit high tolerance to deviations in stoichiometry.…”

“…However, so far most of the characteristics of OVC have not been studied in depth. Only some optical properties, mainly the band gaps E g of Cu 2 In 4 Se 7 and CuGa 3 Se 5 thin films 4,5 and bulk samples [6][7][8][9][10] have been reported so far.…”

Optical and Photoelectric Properties of CuGa5Te8 Single Crystals and In/p-CuGa5Te8 Structures

“…The interest shown by researchers in the complex semiconductor compounds I-III n -VI m (n = 3, 5; m = 5, 8) formed in the A 2 1 C VI -B 2 III C 3 IV cuts, is explained by the prospects for their use in modern semiconductor and quantum electronics [1][2][3][4]. These compounds have also been much investigated because of the necessity of searching for new approaches to the control of fundamental properties of triple chalcogenides [5,6].…”