Effect of thermal annealing in a-In_xGa_1-xN films prepared by reactive RF-sputtering

We deposited amorphous indium gallium nitride (a-In_xGa_1-xN) films at room temperature by reactive radio frequency sputtering with GaN and InN targets and investigated the change of their properties from thermal annealing at annealing temperatures, T_a, below 200 ^oC. A large change in the indium and nitrogen composition ratios was not observed by thermal annealing at a T_a below 200 ^oC. In the X-ray diffraction patterns of the films annealed at a T_a below 200 ^oC, no perceivable peaks assigned to crystalline In_xGa_1-xN were found. The photoconductivty, σ_p, increased with an increase in T_a. On the other hand, the increase of the dark conductivity, σ_d, was very small with an increase in T_a below 200 ^oC. As a result, the photosensitivity, σ_p/σ_d, increased from 252 to 2500 by thermal annealing at a T_a of 200 ^oC. (author)