Optical energy gap measurement of semiconductor ultrathin films using optical waveguides

Naganori Takezawa, Isamu Kato

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)2826-2832
Number of pages7
JournalJapanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
Volume35
Issue number5 SUPPL. A
Publication statusPublished - 1996 May

Fingerprint

Ultrathin films
Optical waveguides
optical waveguides
Film thickness
Energy gap
Semiconductor materials
oscillations
slabs
film thickness
transmittance
Amorphous silicon
amorphous silicon
field strength
Sensors
sensitivity
sensors
simulation

Keywords

  • a-Si:H
  • Band gap
  • Interference fringe
  • Optical energy gap
  • Slab optical waveguide
  • Ultrathin film

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)
  • Engineering(all)

Cite this

Optical energy gap measurement of semiconductor ultrathin films using optical waveguides. / Takezawa, Naganori; Kato, Isamu.

In: Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers, Vol. 35, No. 5 SUPPL. A, 05.1996, p. 2826-2832.

Research output: Contribution to journalArticle

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