LUMINESCENT WAVE-GUIDE STRUCTURES DEPOSITED FROM LIQUID ORGANOSILANE VAPOR SOURCES

Using liquid organosilane vapour sources (e.g. tetramethylsilane, hexa methyldisilane, hexamethyldisilazane) in a plasma enhanced chemical va pour deposition process, we have grown thin films (similar to 1 mu m) of a-SiC:H which show both efficient ultraviolet(UV)-excited photolumi nescence (PL) in the visible spectral range and low self-absorption of the luminescence light. We have investigated the correlations between luminescence and absorption properties by variation of precursor mate rials and of annealing procedures. In the energy range of the luminesc ence absorption coefficients as low as 1 cm(-1) have been obtained tog ether with a PL quantum efficiency of several percent. Based on the lu minescent and low-absorptivity films we have deposited thin film waveg uides on thermally oxidized (1.5 mu m) crystalline silicon or on ordin ary borosilicate glass substrates. These waveguide structures convert incident diffuse UV light into visible light which is captured and tra nsported parallel to the substrate. Moreover, the intensity (in W/m(2) ) of the guided light can be significantly higher than the diffuse UV excitation intensity. The ratio of guided light intensity to UV excita tion intensity can be defined as a quality factor Q which represents a material property of the deposited film. We have prepared a-Si1-xCx:H thin film waveguides with Q > 10 to at room temperature.