Urbach energy parameter of flash evaporated amorphous gallium arsenide films

Low temperature annealing of amorphous gallium arsenide films

“…In an earlier study [18], we found that both optical and electric properties of a-GaAs films depend on crucible temperature and not on As composition (or Ga). All produced samples are As-rich with the arsenic concentrations in the range of 53-57 at.%.…”

“…All produced samples are As-rich with the arsenic concentrations in the range of 53-57 at.%. The films studied here have conductivities at room temperature of $3 Â 10 À6 ðX cmÞ À1 [18] and E 0 $ 120 meV. Their preparation conditions correspond to the smallest conductivities and smallest E 0 s of the series of deposited films, indicating a smaller number of defects in comparison to those of films prepared with other preparation conditions [18].…”

“…The films studied here have conductivities at room temperature of $3 Â 10 À6 ðX cmÞ À1 [18] and E 0 $ 120 meV. Their preparation conditions correspond to the smallest conductivities and smallest E 0 s of the series of deposited films, indicating a smaller number of defects in comparison to those of films prepared with other preparation conditions [18]. The main defects formed in As-rich samples should be As dangling bonds, triply coordinated As sites (C 3 ) [7] and the As-As wrong bonds.…”

Relationship between the optical gap and the optical-absorption tail breadth in amorphous GaAs

“…17 Further details on the preparation of these films, and on their characterization, are provided in the literature. 7,8,18 Measurements of the transmittance and reflectance spectra of these a-GaAs films were obtained using a Lambda-9 Perkin-Elmer spectrophotometer in the visible and nearinfrared ranges. The corresponding optical-absorption spectra were determined using standard thin-film optics techniques.…”

“…As with many other amorphous semiconductors, the optical properties of this material have been the focus of considerable investigation. [4][5][6][7][8] From this research, key insights into the electronic character of a-GaAs have been gleaned.…”