Abstract
We fabricated amorphous silicon (a-Si)-based distributed Bragg reflectors (DBRs) consisting of alternating dense/porous films (i.e., pair) for a center wavelength () of 0.96 μm by oblique angle deposition (OAD) technique using an electron-beam evaporation system. The dense (high refractive index, i.e., high-) and porous (low-) a-Si films were deposited at two incident vapor flux angles of 0° and 80° in the OAD, respectively. Their optical reflectance characteristics were investigated in the wavelength range of 0.6–1.5 μm, including theoretical comparison using a rigorous coupled-wave analysis method. Above three pairs, the reflectivity () of a-Si DBRs was almost saturated at wavelengths around 0.96 μm, exhibiting values of . For the a-Si DBR with only three pairs, a broad normalized stop bandwidth () of was obtained at wavelengths of , keeping high values of . To simply demonstrate the feasibility of device applications, the a-Si DBR with three pairs was coated as a high-reflection layer at the rear facet of GaAs/InGaAs quantum-well laser diodes (LDs) operating at . For the LDs coated with three-pair a-Si DBR, external differential quantum efficiency () was nearly doubled compared to the uncoated LDs, indicating the value of (i.e., for the uncoated LDs).
© 2015 Optical Society of America
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