Monoclinic gallium oxide(Ga_2O_3) has been grown on(0001) sapphire(Al_2O_3) substrate by plasma-assisted molecular beam epitaxy(PA-MBE). The epitaxial relationship has been confirmed to be [010]( 2ˉ01) β-Ga_2O_3||[ ...Monoclinic gallium oxide(Ga_2O_3) has been grown on(0001) sapphire(Al_2O_3) substrate by plasma-assisted molecular beam epitaxy(PA-MBE). The epitaxial relationship has been confirmed to be [010]( 2ˉ01) β-Ga_2O_3||[ 011ˉ0](0001)Al_2O_3 via in-situ reflection high energy electron diffraction(RHEED) monitoring and ex-situ X-ray diffraction(XRD) measurement. Crystalline quality is improved and surface becomes flatter with increasing growth temperature, with a best full width at half maximum(FWHM) of XRD ω-rocking curve of( 2ˉ01) plane and root mean square(RMS) roughness of 0.68° and 2.04 nm for the sample grown at 730 °C,respectively. Room temperature cathodoluminescence measurement shows an emission at ～417 nm, which is most likely originated from recombination of donor–acceptor pair(DAP).展开更多
Two-inch Ga_2O_3 films with（ˉ201）-orientation are grown on c-sapphire at 850–1050°C by hydride vapor phase epitaxy. High-resolution x-ray diffraction shows that pure β-Ga_2O_3 with a smooth surface has a hig...Two-inch Ga_2O_3 films with（ˉ201）-orientation are grown on c-sapphire at 850–1050°C by hydride vapor phase epitaxy. High-resolution x-ray diffraction shows that pure β-Ga_2O_3 with a smooth surface has a higher crystal quality, and the Raman spectra reveal a very small residual strain in β-Ga_2O_3 grown by hydride vapor phase epitaxy compared with bulk single crystal. The optical transmittance is higher than 80% in the visible and near-UV regions, and the optical bandgap energy is calculated to be 4.9 e V.展开更多
Directionally solidified dual-phase Al_(2)O_(3)/Y_(3)Al_(5)O_(12)(YAG)eutectic ceramics(DSECs)typically exhibit strong anisotropy.To improve their properties,various single-phase sapphire seeds,including r-axis[1-102]...Directionally solidified dual-phase Al_(2)O_(3)/Y_(3)Al_(5)O_(12)(YAG)eutectic ceramics(DSECs)typically exhibit strong anisotropy.To improve their properties,various single-phase sapphire seeds,including r-axis[1-102],m-axis[10-10],c-axis[0001],and a-axis[11-20],were used as seeds to induce the orientation of the Al_(2)O_(3)/YAG DSECs.The results showed that Al_(2)O_(3) in the eutectics could be governed by the sapphire seeds.The YAG in each induced eutectic had a specific growth direction endowed by Al_(2)O_(3) in the asinduced eutectics or the sapphire seed.Herein,we calculated the planar lattice misfits and interfacial strain energies of four crystallographic orientation relationships based on the constructed lattice models.It was elucidated the constraint of the sapphire seed caused YAG to grow following the rule of mini-mizing the interfacial strain energy.This revealed the reason why Al_(2)O_(3)/YAG DSECs orientation can be successfully induced.These results may provide a novel method for the design of high-performance eu-tectic ceramic materials.展开更多
Epitaxiai CeO_2 thin films have ben grown on in situ (1102) sapphire subetrate by planar target rf mag-netron sputtering methed. The CeO_2 thin films have perfect (002) orientation with CeO_2(001)∥Al_2O_3(1102). The ...Epitaxiai CeO_2 thin films have ben grown on in situ (1102) sapphire subetrate by planar target rf mag-netron sputtering methed. The CeO_2 thin films have perfect (002) orientation with CeO_2(001)∥Al_2O_3(1102). The X-ray 2θ-θ diffraction, ω scan, Φ scan and electron channelling pattern (ECP) shown that thefilms liave high lattice perfection. The relation of growth conditions and film structure was also studied. Thespudering gas presure and subetrate temperature are the most important parameters preparing fer high qualitybeO_2 films.展开更多
采用气相传输平衡(VTE)技术,在(0001)面白宝石衬底表面上成功地制备出单相-γL iA lO2层。研究了白宝石衬底表面形貌对-γL iA lO2层质量的影响,发现白宝石衬底的表面粗糙度和退火处理是两个影响-γL iA lO2层质量的重要因素。要制备高...采用气相传输平衡(VTE)技术,在(0001)面白宝石衬底表面上成功地制备出单相-γL iA lO2层。研究了白宝石衬底表面形貌对-γL iA lO2层质量的影响,发现白宝石衬底的表面粗糙度和退火处理是两个影响-γL iA lO2层质量的重要因素。要制备高质量的-γL iA lO2层,适度的表面粗糙度是恰当的。对白宝石衬底进行退火处理,-γL iA lO2层的择优取向变差。并对其中可能的机理进行了探讨。展开更多
基金supported by the National Key R&D Program of China(No.2018YFB0406502)the National Natural Science Foundation of China(Nos.61734001,61521004)
文摘Monoclinic gallium oxide(Ga_2O_3) has been grown on(0001) sapphire(Al_2O_3) substrate by plasma-assisted molecular beam epitaxy(PA-MBE). The epitaxial relationship has been confirmed to be [010]( 2ˉ01) β-Ga_2O_3||[ 011ˉ0](0001)Al_2O_3 via in-situ reflection high energy electron diffraction(RHEED) monitoring and ex-situ X-ray diffraction(XRD) measurement. Crystalline quality is improved and surface becomes flatter with increasing growth temperature, with a best full width at half maximum(FWHM) of XRD ω-rocking curve of( 2ˉ01) plane and root mean square(RMS) roughness of 0.68° and 2.04 nm for the sample grown at 730 °C,respectively. Room temperature cathodoluminescence measurement shows an emission at ～417 nm, which is most likely originated from recombination of donor–acceptor pair(DAP).
基金Supported by the National Key Research and Development Program of China under Grant No 2017YFB0404201the Solid State Lighting and Energy-Saving Electronics Collaborative Innovation Center,PAPDthe State Grid Shandong Electric Power Company
文摘Two-inch Ga_2O_3 films with（ˉ201）-orientation are grown on c-sapphire at 850–1050°C by hydride vapor phase epitaxy. High-resolution x-ray diffraction shows that pure β-Ga_2O_3 with a smooth surface has a higher crystal quality, and the Raman spectra reveal a very small residual strain in β-Ga_2O_3 grown by hydride vapor phase epitaxy compared with bulk single crystal. The optical transmittance is higher than 80% in the visible and near-UV regions, and the optical bandgap energy is calculated to be 4.9 e V.
基金financially supported by the National Natural Science Foundation of China(Nos.52171046,51804252,52234010,and 51922068).
文摘Directionally solidified dual-phase Al_(2)O_(3)/Y_(3)Al_(5)O_(12)(YAG)eutectic ceramics(DSECs)typically exhibit strong anisotropy.To improve their properties,various single-phase sapphire seeds,including r-axis[1-102],m-axis[10-10],c-axis[0001],and a-axis[11-20],were used as seeds to induce the orientation of the Al_(2)O_(3)/YAG DSECs.The results showed that Al_(2)O_(3) in the eutectics could be governed by the sapphire seeds.The YAG in each induced eutectic had a specific growth direction endowed by Al_(2)O_(3) in the asinduced eutectics or the sapphire seed.Herein,we calculated the planar lattice misfits and interfacial strain energies of four crystallographic orientation relationships based on the constructed lattice models.It was elucidated the constraint of the sapphire seed caused YAG to grow following the rule of mini-mizing the interfacial strain energy.This revealed the reason why Al_(2)O_(3)/YAG DSECs orientation can be successfully induced.These results may provide a novel method for the design of high-performance eu-tectic ceramic materials.
文摘Epitaxiai CeO_2 thin films have ben grown on in situ (1102) sapphire subetrate by planar target rf mag-netron sputtering methed. The CeO_2 thin films have perfect (002) orientation with CeO_2(001)∥Al_2O_3(1102). The X-ray 2θ-θ diffraction, ω scan, Φ scan and electron channelling pattern (ECP) shown that thefilms liave high lattice perfection. The relation of growth conditions and film structure was also studied. Thespudering gas presure and subetrate temperature are the most important parameters preparing fer high qualitybeO_2 films.
文摘采用气相传输平衡(VTE)技术,在(0001)面白宝石衬底表面上成功地制备出单相-γL iA lO2层。研究了白宝石衬底表面形貌对-γL iA lO2层质量的影响,发现白宝石衬底的表面粗糙度和退火处理是两个影响-γL iA lO2层质量的重要因素。要制备高质量的-γL iA lO2层,适度的表面粗糙度是恰当的。对白宝石衬底进行退火处理,-γL iA lO2层的择优取向变差。并对其中可能的机理进行了探讨。
