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1.
2.
The microstructure of InxGa1−xAs/GaAs (5 nm/5 nm, x < 0 to 1.0), as grown by a metalorganic chemical vapor deposition two-step growth technique on Si(100)
at 450‡C, and subsequently annealed at 750‡C, is investigated using plan-view and cross-sectional transmission electron microscopy.
The variations in resultant island morphology and strain as a function of the In content were examined through the comparison
of the misfit dislocation arrays and moirés observed. The results are discussed in relation to the ways in which the island
relaxation process changes for high In content. 相似文献
3.
Yoon Seok Oh Lingfei Wang Hyungwoo Lee Woo Seok Choi Tae Heon Kim 《Advanced functional materials》2023,33(36):2302261
Growth and characterization of metal-oxide thin films foster successful development of oxide-material-integrated thin-film devices represented by metal-oxide-semiconductor field-effect transistors (MOSFET), drawing enormous technological and scientific interest for several decades. In recent years, functional oxide heterostructures have demonstrated remarkable achievements in modern technologies and provided deeper insights into condensed-matter physics and materials science owing to their versatile tunability and selective amplification of the functionalities. One of the most critical aspects of their physical properties is the polar perturbation stemming from the ionic framework of an oxide. By engineering and exploiting the structural, electrical, magnetic, and optical characteristics through various routes, numerous perceptive studies have clearly shown how polar perturbations advance functionalities or drive exotic physical phenomena in complex oxide heterostructures. In this review, both intrinsic (engraved by thin-film heteroepitaxy) and extrinsic (reversibly controllable defect-mediated disorder and polar adsorbates) elements of polar perturbations, highlighting their abilities for the development of highly tunable functional properties are summarized. Scientifically, the recent approaches of polar perturbations render one to consolidate a prospect of atomic-level manipulation of polar order in epitaxial oxide thin films. Technologically, this review also offers useful guidelines for rational design to heterogeneously integrated oxide-based multi-functional devices with high performances. 相似文献
4.
5.
使用光学显微镜、原子力显微镜和微区喇曼光谱对在纳球光刻图案化GaAs衬底的孔洞区进行金属有机化学气相沉积(MOCVD)进而对InP成核层进行了研究.实验结果表明,该局域表面InP的成核层生长和孔洞的大小、方向、位置关系不大,与MOCVD的生长条件相关.与渐变缓冲层生长相比,在InP的成核层中没有出现穿透位错,其结晶质量随着温度的升高而提高,但其表面粗糙度会随着温度的升高而增加,这个现象可能和它的3D岛状生长有关.AFM测试结果表明,提高Ⅴ/Ⅲ比可以在较低的温度下抑制其表面粗糙度降至纳米量级.微区喇曼光谱测试表明,在适当条件生长下可获得InP成核层的二维生长方式.该研究为进一步基于ART机理在二维图案化GaAs衬底开展InP异质外延研究奠定基础. 相似文献
6.
Linan He Caina Luan Di Wang Yong Le Xianjin Feng Jin Ma 《Journal of the American Ceramic Society》2020,103(4):2555-2561
Zinc stannate (Zn2SnO4) films were deposited on MgO (100) substrates by pulsed laser deposition, and Zn2SnO4 monocrystalline films were obtained by postannealing process. The structures, surface morphologies, and optical properties of the Zn2SnO4 films annealed at different temperatures were investigated in detail. Crystal structure analyses showed that the film annealed at 800°C was single crystal Zn2SnO4 with an inverse-spinel structure. The heteroepitaxial mechanism was further clarified by a schematic diagram, and the epitaxial relationships between the film and substrate were Zn2SnO4 (400) || MgO (200) with Zn2SnO4 [001] || MgO [001]. The obtained Zn2SnO4 films exhibited excellent transparency. The optical band gap of the 800°C-annealed Zn2SnO4 film was about 3.97 eV. The extinction coefficients and refractive indexes of the Zn2SnO4 films annealed at different temperatures as a function of wavelength were analyzed in detail. 相似文献
7.
第三代半导体材料GaN由于具有优良性质使其在微电子和光电子领域有广阔的应用前景,目前制备GaN的方法主要有分子束(MBE)、氯化物气相外延(HVPE)、金属有机物化学气相沉积(MOCVD)。其中HVPE技术制备GaN的速度最快,适合制备衬底材料;MBE技术制备GaN的速度最慢;而MOCVD制备速度适中。因而MOCVD在外延生长GaN材料方面得到广泛应用。介绍了MOCVD法外延生长GaN材料的基本理论、发展概况、利用MOCVD法外延生长GaN材料的技术进展。认为应结合相关技术发展大面积、高质量GaN衬底的制备技术,不断完善缓冲层技术,改进和发展横向外延技术,加快我国具有国际先进水平的MOCVD设备的研发速度,逐步打破进口设备的垄断。 相似文献
8.
Elisa García‐Tabars John A. Carlin Tyler J. Grassman Diego Martín Ignacio Rey‐Stolle Steven A. Ringel 《Progress in Photovoltaics: Research and Applications》2016,24(5):634-644
The evolution of Si bulk minority carrier lifetime during the heteroepitaxial growth of III–V on Si multijunction solar cell structures via metal‐organic chemical vapor deposition (MOCVD) has been analyzed. In particular, the impact on Si lifetime resulting from the four distinct phases within the overall MOCVD‐based III–V/Si growth process were studied: (1) the Si homoepitaxial emitter/cap layer; (2) GaP heteroepitaxial nucleation; (3) bulk GaP film growth; and (4) thick GaAsyP1‐y compositionally graded metamorphic buffer growth. During Phase 1 (Si homoepitaxy), an approximately two order of magnitude reduction in the Si minority carrier lifetime was observed, from about 450 to ≤1 µs. However, following the GaP nucleation (Phase 2) and thicker film (Phase 3) growths, the lifetime was found to increase by about an order of magnitude. The thick GaAsyP1‐y graded buffer was then found to provide further recovery back to around the initial starting value. The most likely general mechanism behind the observed lifetime evolution is as follows: lifetime degradation during Si homoepitaxy because of the formation of thermally induced defects within the Si bulk, with subsequent lifetime recovery due to passivation by fast‐diffusing atomic hydrogen coming from precursor pyrolysis, especially the group‐V hydrides (PH3, AsH3), during the III–V growth. These results indicate that the MOCVD growth methodology used to create these target III–V/Si solar cell structures has a substantial and dynamic impact on the minority carrier lifetime within the Si substrate. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
9.
J. R. Gong S. Nakamura M. Leonard S. M. Bedair N. A. El-Masry 《Journal of Electronic Materials》1992,21(10):965-970
AIGaP and GaP films were deposited on the (100) Si substrates by atomic layer epitaxy (ALE) in the temperature range between
450 and 600°C. Under optimum growth conditions, the growth of GaP and AIGaP was observed to proceed in a two-dimensional (2-D)
fashion in the initial growth stages. These ALE-grown films have better surface morphology when compared with the corresponding
MOCVD-grown films. With an AIGaP buffer layer grown on Si, the subsequent growth of GaAs on the AlGaP-coated Si substrates
tends to proceed as 2-D growth. This avoids island growth and the two-step growth process currently used. 相似文献
10.
L. A. Almeida Y. P. Chen J. P. Faurie S. Sivananthan David J. Smith S. -C. Y. Tsen 《Journal of Electronic Materials》1996,25(8):1402-1405
We have systematically studied the growth of CdTe (lll)B on Si(001)with different atomic step structures, defined uniquely
by miscut tilt angle and direction. X-ray double crystal rocking curve (DCRC) analysis has been used to evaluate the crystalline
quality and twin content of the films. High-resolution electron microscopy has been used to examine the CdTe(lll)B/Si(001)
interface and to follow the microstructural evolution as a function of distance from the interface. Our results show that
the formation of double domains and twins is very sensitive to the tilt parameters. When growth conditions are optimized,
twins are not observed at distances greater than about 2.5 microns from the substrate surface. The best quality films exhibit
a DCRC FWHM of 60 arc sec, for a film thickness of 17 μm, the lowest value ever reported for heteroepitaxial growth of CdTe
on Si or GaAs. In efforts to improve the nucleation process, precursors such as Te and As have been used, and we have shown
that they improve the stability of the heterointerface. 相似文献