The study of optical properties of amorphous thin films of mixed oxides In2O3—SnO2 system, deposited by co-evaporation

Abstract

A discussion of optical properties of mixed oxides InuO3-SnO2 system is presented. Film thickness, substrate temperature, composition (in molar %) and annealing have a profound effect on the structure and optical properties of these films. Initially the increase in band gap with the increase of SnO2 content in In203is due to the increase in carrier density as a result of donor electrons from tin. The decrease in band gap above the critical Sn content is caused by the defects formed by Sn atoms, which act as carrier traps rather than electron donors. The increase in band gap with film thickness is caused by the increase in free carrier density which is generated by (i) Sn atom substitution of In atom, giving out one extra electron and (ii) oxygen vacancy acting as two electrons donor. The decrease in band gap with substrate temperature and annealing is due either to the severe deficiency of oxygen, which deteriorate the film properties and reduce the mobility of the carriers, or to the formation of indium species of lower oxidation state (INS+).

Electronic properties of amorphous zinc tin oxide films by junction capacitance methods

“…The effect of increasing structural disorder with increasing annealing temperature as reflected in the Urbach energy has also been quite well established for the case of amorphous silicon [9]. The same trend was also observed by Anwar et al [8] in the In 2 O 3 -SnO 2 system. The situation with regard to electron transport is less clear.…”

“…For example, the Urbach energy of high-quality amorphous silicon lies in the range of 40-50 meV and the Urbach energy of highperformance CIGS solar cells usually lies below 20 meV. However, these Urbach energies are lower than those measured for the amorphous In 2 O 3 -SnO 2 system, a more comparable material, which were in the range of 160-210 meV [8].…”

The study of electronic conduction in amorphous thin films of Al-In2O3-Al structure deposited by thermal evaporation

“…The parameter W m is approximately equal to the band gap of the material, measured optically. We substitute the measured value of optical band gap (2.5 eV) [15] of 300 nm thick sample deposited at 293 K into Eq. (11).…”

Growth Mechanism and Luminescent Properties of Amorphous SiOx Structures via Phase Equilibrium in Binary System

“…The liquidized small-size ternary droplets, reacting with the surface of Si compared with bulk Si, facilitate more rapid nuclei formation, and hence continuous growth development 34 . In addition, SnO and Sn are mixed with In 2 O 3 , and the Sn 4+ ions originating from the pre-contaminated SnO 2 thick films are distributed on In 3+ sites to facilitate the substitution of Sn 4+ for In 3+ 35 . The additional effects of the roles of In 2 O 3 powder and carrier gas are presented in Supplementary Fig.…”