以電晶體為基礎之高效率與高同調性兆赫輻射源

Abstract

本計畫將開發具高效率與高同調性的兆赫輻射源並研究該輻射背後的物理機制。此輻射源為高偏壓下操作的高遷移率電晶體及異質接面雙載子電晶體。為獲得高效率的兆赫輻射，我們將利用高偏壓加速電晶體內的電子，使其有效激發可以輻射兆赫波的聲子。為探討輻射機制，我們將量測電晶體的(1)輻射效率與(2)輻射偏振度受元件結構、操作溫度及電子濃度的影響。為提昇輻射的同調性，我們將使用有共振腔效果的二維金屬孔洞陣列作為異質接面雙載子電晶體的電極。

The project will (1) develop terahertz radiation sources with high efficiency and high coherence and (2) investigate the underlying physics of the radiation. The sources are high-voltage biased high-electron- mobility transistors and heterojunction bipolar transistors. To obtain efficient radiation, we are to apply high-voltage bias to the transistors to accelerate electrons for efficient excitation of phonons capable of emitting terahertz radiation. To explore the radiation mechanism, we are to measure the dependences of (1) the radiation efficiency and (2) the degree of polarization of the radiation on the structural parameters, the operating temperature, and the electron concentration of the transistors. To enhance the coherence, we are to integrate a two-dimensional metallic hole array, which can act as an electrode and provide a cavity effect, with a heterojunction bipolar transistor.