N_2流量对GaN的形貌及光学和电学性能的影响

Effect of N_2 Flow Rate on Morphology, Optical and Electrical Properties of GaN

采用化学气相沉积法(CVD)在Si(100)衬底上以Ni为催化剂,金属Ga和NH3为原料合成了GaN微纳米结构,并研究了N2流量对产物GaN的形貌及光学和电学性能的影响。利用场发射扫描电子显微镜(SEM)、透射电镜(TEM)、X射线衍射仪(XRD)、Xray能谱仪(EDS)、光致发光谱(PL)和霍尔效应测试仪(HMS-3000)等测试手段对样品的形貌、结构、成分、光学和电学性能进行了分析。结果表明,随着N2流量的增加,产物GaN的形貌发生了由微米棒到蠕虫状线再到光滑纳米线的转变;生成的GaN均为六方纤锌矿结构;样品均表现出383 nm的近带边紫外发射峰和470 nm左右的蓝光发射峰;所有样品均为p型;并对产物GaN的形貌转变机理进行了分析。

GaN micro/nanostructures were synthesized by chemical vapor deposition method （CVD） on Si （100） substrate with catalyst Ni, Ga and NH3 as raw materials. Effect of N2 flow rate on the morphology as well as optical and electrical properties of GaN were researched. The morphology, Structure, composition, optical and electrical properties were characterized by Field emission scanning electron microscopy （SEM）, Transmission electron microscopy （TEM）, X-ray diffraction （XRD）, Energy dispersive X-ray spectroscopy （EDS）, Photoluminescence （PL） and Hall effect measurement system （HMS-3000）. The results indicate that with the increase of N2 flow rate, the morphology of GaN evolved from microrods to vermicular-like wires and then to smooth nanowires. All samples are hexagonal wurtzite, and show near-band-edge UV emission peaks of 383 nm and blue light emission peaks of about 470 nm. Hall test results show that all samples are p-type. Furthermore, the morphology evolution mechanisms of GaN are analyzed.