Measurement of the optical energy gap (Eo) using a slab optical waveguide (SOW) has been studied. With increasing hydrogenated amorphous silicon (a-Si:H) film thickness, transmittance was found to decrease with periodic oscillation. It has been clarified that the oscillation is caused by the change of the field strength distribution of a guided mode in a-Si:H according to the increase of a-Si:H film thickness, using the four-layer structure SOW simulation. By removing the oscillation due to the dependence of transmittance on a-Si:H film thickness, the influence of the oscillation on the values of Eo can be eliminated. As a result, it has been demonstrated that Eo of a-Si:H with thickness on the order of 1/40 that of samples used in the conventional method can be measured. It has been clarified that sufficient absorption to determine Eo of a-Si:H ultrathin films is obtained because the sensitivity of the sensor is increased by changing the size of the SOW.
|ジャーナル||Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers|
|号||5 SUPPL. A|
|出版ステータス||Published - 1996 5月|
ASJC Scopus subject areas