Annual Report 2013–14

新型光電檢測器 電子工程學系曾漢奇教授（左一）和 許建斌教授（右一）及其科研團隊， 發明了一項新型光電檢測器，有效推 進高效率低成本紅外光譜技術，可應 用於環境和生物醫學工程，如監測空 氣污染和分析人類呼吸疾病標記。 曾教授和許教授帶領的科研團隊利用 透明膠帶，從石墨中機械剝離出單一 碳原子層的石墨烯，並將石墨烯置於 矽懸浮薄膜光波導路的頂部，製作出 異質結構的光探測器。該器件在室 溫下具有很寬的光譜探測範圍。這項 突破性的實驗進展，有望實現高效 率、低成本、高集成度的中紅外新 一代光探測器。科研團隊證明，利用 單層石墨和矽光波導製作的異質結中 紅外探測器具有很高靈敏度。 科研團隊製作了用於中外光譜探測的 新型光探測器，可用來檢測微量的氣 體濃度（十億分之幾），因此在化光 譜具有很多應用，如空氣污染監測、 氣體「指紋」檢測、以及分析人類 呼吸疾病標記。 研究結果在2013年9月發表於國際學 術期刊《自然─光子學》。 Groundbreaking Development in Mid-IR Photo Detection Prof. Tsang Hon-ki ( 1st left ) and Prof. Xu Jianbin ( 1st right ) and their research team at the Department of Electronic Engineering have constructed a new device for detecting light in the mid-infrared (mid-IR) spectral region. This groundbreaking work is expected to enable a new generation of high efficiency, low cost, and highly integrated mid-IR detectors which proceeds to the applications of mid-IR spectroscopy in environmental and biomedical engineering. Led by Professor Tsang and Professor Xu, the CUHK research team placed the graphene, which is a single layer of carbon atoms that could be obtained by 'scotch tape' mechanical exfoliation from graphite, on the top of a silicon suspended membrane optical waveguide, to make a heterostructure photodetector. The device could operate over a wide range of wavelengths at room temperature. This groundbreaking work is expected to enable a new generation of high efficiency, low cost, and highly integrated mid-IR detectors. The research team proves that the heterostructure formed by placing monolayer graphene on silicon optical waveguide can detect mid-IR light with high sensitivity. The research team constructed a new device for detecting light in the mid-infrared (mid-IR) spectral region. The chemical spectroscopy can detect trace concentrations (parts per billion) of gases for enormous applications, such as air pollution monitoring, gas 'finger-print' sensing, and analysis of human breath for disease markers. The research results were published in Nature Photonics in September 2013 . 23