氮化銦及高銦組成氮化鎵銦量子點及相關異質微結構之光電物理行為研究

Abstract

由於 InN 材料具有高載子遷移率、低能隙值與高△Ec 值，使得InN 材料之 運用可以包括高速、高頻電子元件、1.3-1.55 μm 之光通訊元件及高溫度、高功 率穩定性之光電元件製作。此外在InGaN 合金材料中經由適當調配其固相組成 比例，將可以獲得發光波長範圍涵蓋紫外光、可見光到遠紅外線波段，未來極有 潛力運用於全彩白光固態光源之製作。另一方面，InGaN 合金光電元件可有效 的將太陽光的紅外至紫外光完整頻譜轉換成電流，可望成為有史以來最具效能、 堅固且相對上廉價的太陽能材料。因此InN 及InGaN 材料目前已經引起了產業 界、世界各學術研究單位競相投入研究發展之材料。 迄今本實驗室累積了多年在 III 族氮化物上的研究經驗，目前已有初步的研 究成果，包含已達世界最高之載子遷移率1300 cm2/Vs，螢光光譜半高寬值達70 meV 的InN 薄膜；組成變化由60%至95%之高In 組成InGaN 奈米粒，發光波長 涵蓋1.1~1.6 μm；發光譜峰在1.07 eV、高度6 nm 具有量子效應之InN 奈米粒等， 然而這些初步成果相較於其他III-V 族材料如GaN 或InAs 材料，仍有很大的改 善空間，例如半高寬可以提升至30 meV，電子遷移率可朝理論值的4400 cm2/Vs 推進等，而其關鍵仍在於反應腔之設計。有鑑於此，本計劃將從新設計組裝一適 合低溫成長InN 與高In 組成InGaN 材料又兼具高溫成長高品質GaN 材料之反應 腔體以進一步提升薄膜品質。 基於本研究團隊多年來在於三—五族材料磊晶及光電研究之成果及經驗 上，依據上述初步成果，研究InN 及In-rich InGaN 奈米點溫度相關之類S-shaped 機制研究、高銦組成薄膜載子侷域態研究、高密度奈米點間激子傳輸效應、奈米 點量子侷限效應、薄膜及奈米結構之介面應力與壓電場效應、多重波長堆疊結構 之載子偶合特性研究及InN 單光子光源時間相關特性研究。

Because of the high carrier mobility, low energy gap, and high conduction-band offset of InN material, its application is suitable for opto-electrcal devices, such as high speed and frequency transistor, optical communication device operated at 1.3-1.55 μm, and high power and high temperature device. In addition, by modifying alloy composition inside InGaN, the emission wavelength would range from UV to far infrared, which has great potential for full-color white light source. This material is also capable for transfer solar spectrum, from UV to infrared, to current signal and become the most efficient, reliable, and cheep candidate for solar cell. Thus many industries and laboratories rush for studying the properties of InN and InGaN material recently. Up to date, our laboratory has many experiences on III-nitride study, such as InN films with the highest mobility value 1300 cm2/V-s and the FWHM of PL emission with 70 meV, the In-rich InGaN nano-particles emitted from 1.1~1.6 μm, and the InN nano-particle with 6nm height and 1.07eV emission. However, these primary results can still be improved. We expect the FWHM would be lower to 30 meV and the mobility be approached to 4000 cm2/V-s as theoretical calculation. The critical factor of the improvement is considered as the design and modification of reactor. We thus design a new MOCVD chamber that is suitable for low-temperature growth of InN and In-rich InGaN, as well as for high-temperature growth of GaN films to increase films quality. According to preliminary results, the mainly research topics are focus on the mechanism of InN and In-rich InGaN quantum dots temperature-dependence S-shaped like behavior, localization effect of In-rich InGaN films, carrier transportation effect between dots for high dot density of InN and In-rich InGaN, quantum dot confinement effect, interface strain and piezoelectric effect of InN and In-rich InGaN films and dots, multi-wavelength and multi-stack carrier coupling properties of dots, and InN single photon source time correlation studies.