Study of optical devices with memory function

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K13339
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Applied materials
• Research Institution: Hiroshima University
• Principal Investigator: Yokoyama Shin 広島大学, ナノデバイス・バイオ融合科学研究所, 教授 (80144880)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: 光メモリスタ / ジアリールエテン / ニューラルネットワーク / 光導波路 / シリコン窒化膜 / 紫外線硬化樹脂 / 緑色光透過率 / フォトクロミック材料

Outline of Final Research Achievements

As a fourth element following a resistor, an inductor, and a capacitor, a "memristor" whose resistance changes in accordance with the amount of passed charges attracts attention. In this research, we realized "optical memristor whose optical transmittance changes according to the amount of light passing through".
An optical waveguide including a photochromic material "diarylethene" (discovered by Prof. Irie, Rikkyo University in 1988) in clad or core was fabricated. Its transmittance is reduced by UV irradiation and is recovered by irradiation of green light. However, the recovery time constant by green light is as long as 0.2 s to several minutes and does not reach the target millisecond. Therefore, simulation of the experimental result was carried out by setting up a physical model. As a result it was predicted that when the diarylethene concentration is lowered, the recovery time becomes a millisecond.

Free Research Field

半導体工学