Semipolar GaN Layers Grown on Nanostructured Si(100) Substrate

We propose a new method for growing semipolar GaN films on a Si(100) substrate with an array of sub-100-nm-sized V-grooves formed on the surface. It is shown that, using such a nanostructured substrate for metalorganic hydride vapor-phase epitaxy, it is possible to obtain GaN (101?1?) epilayers deviating by an angle of about 62° from the polar direction and having an X-ray rocking curve with a minimum FWHM value of ω_θ ~ 60 arcmin.     

Si(111)衬底上六方YMnO3薄膜的制备与铁电性质

采用化学溶液法在Si(111)衬底上制备了YMnO3薄膜.XRD结果表明,所制备的薄膜为六方纯相YMnO3,且具有部分择优取向生长.以Pt为顶电极,测试了YMnO3薄膜的电滞回线,结果表明,所制备的YMnO3薄膜具有良好的铁电性质.     

不同射频溅射功率下直接制备Ca_2Si薄膜(英文)

磁控溅射系统在恒定Ar气压和Ar气流流量下,使用不同射频溅射功率在Si(100)衬底上分别沉积Ca薄膜;随后,800℃真空退火1 h.立方相的Ca2Si薄膜首次、单独、直接生长在Si(100)衬底上.实验结果指出,在多相共生的Ca-Si化合物中,沉积Ca薄膜时的射频溅射功率影响了立方相Ca2Si薄膜的质量;最优化的溅射功率是85 W.另外,退火温度为800℃时,有利于单一相Ca2Si的独立生长.并且,退火时间也是关键因素.     

Vapor-Phase Epitaxy of AlN Layers on AlN/Si(111) Templates Synthesized by Reactive Magnetron Sputtering

Technical Physics Letters - Epitaxial aluminum nitride (AlN) layers on Si(111) substrates have been grown by sequential application of several techniques including reactive magnetron sputter...     

Epitaxy of GaN(0001) and GaN(10 $$\bar {1}$$ 1) Layers on Si(100) Substrate

Technical Physics Letters - Two different approaches to epitaxy of 4-μm-thick layers of polar GaN(0001) and semipolar GaN(10 $$\bar {1}$$ 1) on a V-shaped nanostructured Si(100) substrate with...     

Si（100）预结构基底对Si雕塑薄膜三维模拟生长的影响

建立一个雕塑薄膜三维生长的蒙特卡罗模型,模拟在PVD方法下Si在Si（100）基底上沉积的生长,考虑周期性排列预结构基底的阴影效应,模拟不同预结构单元宽度、间距及不同入射角度下斜柱状雕塑薄膜的三维形貌。结果表明,在入射角和宽度一定时,存在一个最佳间宽比值使得薄膜表面粗糙度最小;当宽度大于一定数值,粗糙度随间宽比值增大而...     

Characterization of 4H-SiC grown on AlN/Si(100) by CVD

By using chemical vapor deposition method, 4H-SiC films have been grown on AlN/Si(100) complex substrates at the temperature below 1100 °C. Substitutional Al and N are found in the SiC film. Photoluminescence (PL) peaks, related to Al acceptor and N shallow donor, respectively, have been observed at the room-temperature. The higher partial pressure ratio of SiH₄ and C₂H₄ (P_C2H4 / P_SiH4 ≧ 1.62) results in more Si-vacancy (V_Si) in the film. The PL peak related to the V_Si acceptor level is also observed.     

Hydride Vapor-Phase Epitaxy of a Semipolar AlN(10$$\bar {1}$$2) Layer on a Nanostructured Si(100) Substrate

Technical Physics Letters - We propose a method for the synthesis of hexagonal AlN layer on Si(100) substrate with a V-groove nanostructured surface where the angle between the sloped nanoridge...     

Wafer-Scale Single Crystal Hexagonal Boron Nitride Layers Grown by Submicron-Spacing Vapor Deposition

The direct growth of wafer-scale single crystal two-dimensional (2D) hexagonal boron nitride (h-BN) layer with a controllable thickness is highly desirable for 2D-material-based device applications. Here, for the first time, a facile submicron-spacing vapor deposition (SSVD) method is reported to achieve 2-inch single crystal h-BN layers with controllable thickness from monolayer to tens of nanometers on the dielectric sapphire substrates using a boron film as the solid source. In the SSVD growth, the boron film is fully covered by the same-sized sapphire substrate with a submicron spacing, leading to an efficient vapor diffusion transport. The epitaxial h-BN layer exhibits extremely high crystalline quality, as demonstrated by both a sharp Raman E_2g vibration mode (12 cm⁻¹) and a narrow X-ray rocking curve (0.10°). Furthermore, a deep ultraviolet photodetector and a ZrS₂/h-BN heterostructure fabricated from the h-BN layer demonstrate its fascinating properties and potential applications. This facile method to synthesize wafer-scale single crystal h-BN layers with controllable thickness paves the way to future 2D semiconductor-based electronics and optoelectronics.     

2D AlN Layers Sandwiched Between Graphene and Si Substrates

Due to the superior thickness‐dependent properties, 2D materials have exhibited great potential for applications in next‐generation optoelectronic devices. Despite the significant progress that has been achieved, the synthesis of 2D AlN remains challenging. This work reports on the epitaxial growth of 2D AlN layers via utilizing physically transferred graphene on Si substrates by metal–organic chemical vapor deposition. The 2D AlN layers sandwiched between graphene and Si substrates are confirmed by annular bright‐field scanning transmission electron microscopy and the effect of hydrogenation on the formation of 2D AlN layers is clarified by theoretical calculations with first‐principles calculations based on density functional theory. Moreover, the bandgap of as‐grown 2D AlN layers is theoretically predicted to be ≈9.63 eV and is experimentally determined to be 9.20–9.60 eV. This ultrawide bandgap semiconductor shows great promise in deep‐ultraviolet optoelectronic applications. These results are expected to support innovative and front‐end development of optoelectronic devices.     

Properties of ZnO Thin Films Grown on Si (100) Substrates by Pulsed Laser Deposition

ZnO thin films were grown on Si (100) substrates by pulsed laser deposition using a ZnO target.The substrate temperature was varied in the range of room temperature to 800 ℃,and the oxygen partial pressure of 0.1333 Pa (1 m Torr) to 1333 Pa (10 Torr).The properties of the resulting films were investigated by photoluminescence (PL),grazing incidence X-ray diffraction (GIXRD),X-ray photoelectron spectroscopy (XPS),and field emission scanning electron microscopy (FESEM).Based on the ultraviolet (UV,～380 nm) to...     

脉冲激光沉积法在Si(111)衬底上生长高c轴取向LiNbO3薄膜

在氧压20Pa,衬底温度600℃,靶材与衬底距离4cm的最优化条件下,利用脉冲激光沉积(PLD)技术首次在无诱导电压和任何缓冲层的情况下,在单晶Si(111)衬底上生长具有优良结晶品质和高c轴取向的LiNbO3晶体薄膜.利用X射线衍射(XRD)、扫描电子显微镜(SEM)和原子力显微镜(AFM)对LiNbO3薄膜的结晶品质,择优取向性以及表面形貌进行了系统的分析.结果表明生长出了具有优异晶体质量的c轴取向LiNbO3薄膜,表面光滑平整且无裂纹产生,表面粗糙度约4.8nm,有利于硅基光电子器件的制备和利用.     

Surface Topography and Optical Properties of Thin AlN Films Produced on GaAs (100) Substrate by Reactive Ion-Plasma Sputtering

Technical Physics Letters - A study of the surface topography and optical characteristics of thin AlN films used as passivating and antireflection coatings deposited on n-GaAs (100) substrates by...     

湿法腐蚀硅片并生长氧化锌纳米棒作为太阳能电池减反层研究

在硅基太阳能电池表面制备减反层可以有效降低硅表面的反射率, 提高吸收率, 从而提高硅基太阳能电池的光电转换效率。本研究利用四甲基氢氧化铵(Tetramethyl Ammonium Hydroxide TMAH)溶液对(100)单晶硅进行各向异性腐蚀, 在表面腐蚀出金字塔结构, 得到了最低为6%左右的反射率。然后采用水热法在该衬底生长氧化锌纳米棒, 得到了最低小于3%的反射率, 比单采用腐蚀或者ZnO纳米棒生长的硅表面的反射率更低。这种减反方法工艺简单、高效, 有望得到应用。     

Si_(0.75)Ge_(0.25)虚衬底上应变补偿Si/Si_(0.62)Ge_(0.38)量子阱发光

由于Si/SiGe异质结构的带阶差主要发生在价带,为实现高效率的发光,本文从理论上设计了在硅基Si1-xGex虚衬底上外延应变补偿的Si/S1-yGey(y>x)量子阱的能带结构,将量子阱对电子的限制势垒提高到100meV以上。在实验上,采用300℃生长的Ge量子点插入层,制备出薄的SiGe驰豫缓冲层(虚衬底),表面Ge组份达到0.25,表面粗糙度小于2nm,驰豫度接近100%。在我们制备的SiGe缓冲层上外延了应变补偿SiGe/Si多量子阱结构,并初步研究了其发光特性。     

Si(111)衬底上生长的立方MgxZn1-xO晶体薄膜

在国际上第一次采用电子束反应蒸发法在Si(111)衬底上生长了MgxZn1-xO晶体薄膜.能量色散X射线(EDX)特征能谱及X射线衍射(XRD)分析表明薄膜呈立方结构,薄膜的晶面取向依赖于生长温度,在200C温度下生长得到高度(200)取向的立方MgxZn1-xO薄膜,温度过高时得到多晶薄膜.对高度(200)取向的立方MgxZn1-xO薄膜的光荧光激发谱(PLE)分析表明其光学带隙为4.20eV,相对于MgO的带隙红移量为3.50eV.XRD分析还表明立方MgxZn1-xO薄膜与MgO衬底之间的晶格失配仅为0.16%.这使得高质量立方MgxZn1-xO/MgO多量子阱材料的制备成为可能.     

硅、锗材料在Si(100)表面的生长研究

利用扫描隧道显微镜和超高真空实验装置系统进行了Si(10 0 )表面生长Si,Ge的实验研究。分析了所生成表面的形貌、结构等物理性质。研究表明 :Si在Si(10 0 )表面的同质生长可以形成纳米结构薄膜。Ge在Si(10 0 )表面生长形成规则的三维小岛。而在Si/Ge/Si(10 0 )多层膜上生长则形成大小二种三维岛。研究表明大岛具有Ge/Si/Ge的壳层结构