利用電漿輔助化學氣相沉積法於低溫下成長氮化鎵奈米線

本文主要以電漿輔助化學氣相沉積法藉由氣－液－固成長機制（vapor-liquid-solid mechanism, VLS）成長氮化鎵（gallium nitride, GaN）奈米線。此實驗系統以氮電漿作為氮化鎵成長所需的氮源，氮電漿反應性比熱化學氣相沉積法所使用的氨氣高且氮電漿解離率與溫度間的關聯性不大，故能在低成長溫度下得到高品質氮化鎵奈米線。在本研究中，氮化鎵奈米線的成長溫度範圍由900°C到550°C，以穿透式電子顯微鏡（transmission electron microscopy, TEM）、光激發螢光光譜（photoluminescence, PL）及X光繞射儀（X-ray diffraction, XRD）對製備出的氮化鎵奈米線進行分析。相較於熱化學氣相沉積法需要接近1000°C的高溫來成長高品質晶體，利用電漿輔助系統可在900°C下成長出高品質的氮化鎵奈米線，當成長溫度下降到700°C時，經由TEM與PL的分析，證實在這個系統中仍可維持奈米線的晶體品質，但當成長溫度降到550°C 時，由於成長氣氛轉為N-rich及低的表面溫度，造成鎵原子在基板及奈米線表面的擴散能力大幅下降，奈米線內部及表面因而產生許多缺陷，使奈米線外型彎曲且晶體品質下降。

關鍵字

電漿輔助化學氣相沉積法；氮化鎵；奈米線

並列摘要

In this work, a novel plasma-assisted chemical vapor deposition method was developed to fabricate GaN nanowires by the Vapor-Liquid- Solid Mechanism. Nitrogen plasma was used as a nitrogen source to grow GaN crystals. Compared to NH(subscript 3) used in thermal CVD systems, nitrogen plasma is more active and its ability to produce active nitrogen radicals is insensitive to temperature, making it more suitable for low temperature growth of GaN crystals. The growth temperature of GaN nanowires varied from 900 to 550°C followed by transmission electron microscopy (TEM), photoluminescence (PL) and X-ray diffraction analysis to investigate the effect of growth temperature on the crystal structure and quality. High quality GaN nanowires were grown at 900°C, which was lower than the normal growth temperature of 1000°C in thermal CVD. According to TEM and PL analysis, the crystal quality was still high, even after lowering the growth temperature to 700°C. When the growth temperature was further reduced to 550°C, defects formed in the bulk and on the surface of nanowires due to the slow surface diffusion of Ga adatoms on the sidewall of nanowires resulting from the N-rich growth environment and low surface temperature.

並列關鍵字

PECVD ； GaN ； Nanowires

國際替代計量

利用電漿輔助化學氣相沉積法於低溫下成長氮化鎵奈米線

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