鍺金氧半發光元件

Abstract

本論文中，我們報告了從鍺金氧半二極體所發出的紅外光的特性，並且觀察到接近1.8微米的發光波長。我們也使用了電子-電洞-電漿模型來分析發光頻譜，得到了頻譜的理論線以及能隙的理論值。鍺的發光強度比矽強，可能的原因是鍺有較高的發光複合效率以及需要較少的晶格動量來達成複合發光時的動量守恆。為了了解不同的閘極金屬材料對鍺金氧半發光元件的影響，我們研究了鋁閘極和鉑閘極元件的特性。在同樣的操作電流下，鋁閘極元件的光強度比鉑閘極元件強。 我們也研究了應變鍺金氧半發光元件的發光特性，藉著使用外加應變的機械裝置，我們在鍺金氧半發光元件上施加了雙軸應變以及單軸應變。由於應變使得鍺的能隙變小，進而使得發光頻譜有紅位移的現象發生，而雙軸應變所造成的能隙減少較單軸應變多。 最後，我們使用鍺金氧半二極體在空氣中傳送光信號。藉由不同的操作原理，鍺金氧半二極體可以發射或偵測光子。而資料傳輸的速度可以達到15百萬赫茲或更快。

In this thesis, we present the infrared emission from Ge metal-oxide-semiconductor (MOS) tunneling diodes. The peak emission wavelength of ~1.8μm is observed. The electron-hole-plasma model is then used to get the fitting line of the emission spectra and the theoretical band gap energy values. It is observed that the emission light intensity of Ge is stronger than Si, where possible reasons may be the higher radiative recombination rate and the slightly smaller wave vector needed to conserve momentum in Ge. To understand the influences of different metal gate materials on the performance of Ge MOS light-emitting device (LED), the characteristics of Al and Pt gate devices are investigated. Al gate devices have stronger emission than Pt gate devices under the same injection current operation. The emission properties of strained-Ge MOS LED are also investigated. Using the external strain mechanism, we apply biaxial and uniaxial strain on the Ge MOS LED. The emission wavelength of strained-Ge MOS LED is redshifted due to the band gap reduction, and biaxial strain can give more band gap reduction than uniaxial strain. Finally, we transfer optical signals between Ge MOS tunneling diodes in free space. The Ge MOS tunneling structure can emit and detect photons through different operation principles. The transmission rate can reach 15MHz or higher.