Highly-reflective and conductive distributed Bragg reflectors based on glancing angle deposited indium tin oxide thin films for silicon optoelectronic applications

We investigated the highly-reflective and conductive indium tin oxide (ITO) single material-based distributed Bragg reflectors (DBRs), operating at a center wavelength of 565 nm, by a glancing angle deposition method. The porous ITO films were formed at an incident vapor flux angle of 80°, indicating the effective refractive index of ~ 1.258. The optical properties (e.g., reflectance and normalized stop bandwidth) were enhanced as the number of pairs was increased. The maximum reflectance and normalized stop bandwidth for the high reflectance region of > 80% were estimated to be ~ 85% and ~ 8%, respectively. Furthermore, the incident angle-dependent reflectance characteristics were also investigated in the incident angle range of 20-60° for p-, s-, and non-polarization. For comparison, the theoretical optical modeling and simulation were performed using the rigorous coupled-wave analysis method, exhibiting a similar tendency with the experimental results. The effective electrical characteristics of ITO DBRs were also obtained.