開發結合電晶體與微共振腔之高效率兆赫波輻射源

Abstract

本計畫旨於研發高效率且可電調制的兆赫波段窄頻輻射源。此輻射源由高電子遷移 率電晶體與金屬-半導體-金屬形式的微共振腔所組成。透過高電場激發電晶體，材料 中的聲子能被有效地激發並進一步貢獻兆赫波輻射。輻射效率除可藉由增加輸入功率 提升外，亦可透過選擇性地移除電晶體下方的基板而獲得提升。為獲得窄頻輻射，我 們將電晶體的電極設計成為微共振腔的一部分。輻射頻率可隨電極形狀與大小調整， 而元件的輻射率可透過改變半導體薄膜的厚度予以最佳化。

In this two-year term project, we will develop electrically modulated narrowband radiation sources with high efficiency in the terahertz regime. The sources will be a metal-semiconductor-metal structure consisting of a high electron mobility transistor and a microcavity. Phonons will be generated efficiently in the transistor under high-field excitation, leading to intense terahertz radiation. Radiation efficiency can be enhanced either by increasing input power or by selectively removing the substrate underneath the transistors. The electrodes will be elaborately designed and integrated with the microcavity to reach narrowband radiation. We will also investigate the relationship between the radiation frequency and the geometrical properties, such as the shape and size, of the electrodes. The radiation efficiency depends also on the structure thickness and the relationship will be studied.