Luminescence Properties of GaAs Epitaxial Layers Grown By Liquid Phase Epitaxy and Molecular Beam Epitaxy

1980 ◽  
Vol 2 ◽  
Author(s):  
P. M. Petroff
Keyword(s):  
Liquid Phase ◽  
Molecular Beam Epitaxy ◽  
Liquid Phase Epitaxy ◽  
Scanning Transmission Electron Microscopy ◽  
Molecular Beam ◽  
Degradation Process ◽  
Luminescence Properties ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Laser Devices

ABSTRACTThe luminescence properties of undoped GaAs-Ga1−x Alx As layers grown by liquid phase epitaxy (LPE) and molecular beam epitaxy (MBE) are compared for double heterostructure and multiquantum well (MQW) superlattices. Low temperature cathodoluminescence and scanning transmission electron microscopy are used to identify the main luminescence centers and in some instances establish their origin. The possible effects of the observed luminescence features on the degradation process in GaAs-Gal−x Alx As laser devices grown by MBE and LPE are also discussed.

Structural and Chemical Characterization of Al(Ga)N/GaN Quantum Well Structures Grown by Plasma Assisted Molecular Beam Epitaxy

2012 ◽  
Vol 186 ◽  
pp. 70-73 ◽  
Author(s):  
Jolanta Borysiuk ◽  
Piotr Dłużewski ◽  
Zbigniew Zytkiewicz ◽  
Marta Sobańska ◽  
Kamil Kłosek ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Molecular Beam Epitaxy ◽  
Scanning Transmission Electron Microscopy ◽  
Molecular Beam ◽  
Chemical Characterization ◽  
Quantum Well Structures ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Electron Energy Loss

Growth of high quality GaN/AlN heterostructures by plasma assisted molecular beam epitaxy (PAMBE) is possible with excess of Ga on the surface. During growth of AlN this additional Ga acts as surfactant and improves mobility of the Al adatoms on the growing surface, at the possible cost of Ga segregation and creation of mixed AlGaN interlayer. Scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy (EELS) were used to determine chemical composition of high crystallographic quality GaN-AlN multilayer structure. It was shown that segregation occurs at AlN-GaN heterointerfaces, while GaN-AlN interfaces have abrupt stepwise change of the chemical composition. HRTEM results show creation of trench defects at the periphery of growing AlN islands in the case of nonoptimized growth.

Quantitative EELS Analysis of AlGaN Nanowires Grown by Ni Promoted MBE on Sapphire Substrate

2007 ◽  
Vol 1026 ◽  
Author(s):  
Leonardo Lari ◽  
Robert T Murray ◽  
Mhairi H Gass ◽  
Timothy J Bullough ◽  
Paul R Chalker ◽  
...  
Keyword(s):  
Solid Solution ◽  
Scanning Transmission Electron Microscopy ◽  
Molecular Beam ◽  
Equilibrium Phase ◽  
Oxide Shell ◽  
Transmission Electron ◽  
Frequency Plasma ◽  
Scanning Transmission ◽  
Electron Energy Loss ◽  
N Compounds

AbstractQuantitative analysis of the elemental distributions within AlGaN has been investigated using electron energy loss spectroscopy in a scanning transmission electron microscopy. The nanowires were grown on c-sapphire by radio frequency plasma assisted molecular beam epitaxy. Crystallographic and compositional analyses of the nickel seeds used to promote the nanowire type growth yielded values of lattice spacings within the seeds remaining at the growth tip which were attributed to either (002) NiO, (111) Ni3Ga or (111) Ni-Ga solid solution. The seeds structures exhibited a metallic core encompassed by an oxide shell. The relative gallium and nickel concentrations were quantified by EELS analyses and were found to be consistent with the equilibrium phase α' of Ni3Ga or Ni-Ga solid solution. No nitrogen was observed within the seeds, which is predicted thermodynamically due to the instability of Ni-N compounds at the NW growth temperature used in this study. No aluminium was detected at the tip of nanowires. These measurements are compared with previous studies made concerning pure GaN nanowires. The Al distribution along the nanowire length was measured and is discussed in respect of a possible Al incorporation mechanism.

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