无籽晶化学气相法生长ZnO晶体

Growth of ZnO Single Crystal by Unseeded Chemical Vapor Transport Method

采用化学气相法自发成核的方式生长出Φ4 mm×5 mm ZnO单晶体。分析了化学气相输运机制,获得ZnO-C体系在生长过程中的压强为0.43 MPa,确定以扩散传输为主;设计了新的生长石英安瓿（锥角约为35°）,让沿较快面生长的晶核能淘汰其他晶胚,易长大并形成单晶;X射线衍射测试晶体生长显露面为（002）面,其回摆曲线半峰宽为18 arcsec;六边形的腐蚀蚀坑确定该面为ZnO（001）的Zn面,位错缺陷密度为103cm-2量级。晶体在368 nm处出现了较强的紫外发光峰,属带边激子跃迁;紫外透过率在450~1000 nm内达65%,截止波长为390 nm,对应禁带宽度约为3.12 e V。结果表明,采用无籽晶化学气相法生长的ZnO晶体结晶度好,质量较高。

A ZnO single crystal with Φ4 mm × 5 mm were grown by chemical vapor phase method with spontaneous nucleation. The transport mechanism is analyzed,and the pressure of ZnO-C system is about0. 43 MPa in the growth process,and diffusion was confirmed as the major mechanism of mass transfer.The conical ampoule（ the cone angle of 35°） was designed to control the spontaneous nucleation,it aims to let growth tends gradually to mononuclear crystal growth by geometry eliminate. The（ 002） reflection has been found from sharp X-ray rocking curve with the full width at half-maximum of 18 arcsec,and Zn surface of the（ 001） face was identified from the hexagonal structure observed in the corrosion morphology,then the etch pit density of this reflection was calculated as 103cm-2. The crystal has a narrow and strong ultraviolet light emitting peak at 368 nm,which attributed to the band edge excitonic transition. Ultraviolet transmittance was about 65% within 450-1000 nm,and the forbidden band width is found as 3. 12 e V. The results show that the crystallinity and quality of as-grown ZnO single crystal were high.