Papers by Keyword: Molecular Beam Epitaxy (MBE)

Abstract: We present a new possibility of crystal growth as synthesis of materials containing high concentrations of unpaired sp electrons by growth of Be doped Gallium Arsenides at low temperatures of 200-3000C using Molecular Beam Epitaxy (MBE) and investigate a possibility of applications of magnetotransport properties based on these unpaired sp-electrons to spintronics devices.The present study using high concentration of unpaired sp-electrons by the growth of Beryllium-doped GaAs layers at low temperatures resulted in a cooperative transition of localized spins at low temperature and also affected the mechasnism of tranport properties of the sample from hopping conduction to valence band conduction.This attempts will give rise to a possibility of adding new functions to existing electronic devices.

Abstract: Artificial super-lattices of [(BaTiO3)/(SrTiO3)10]4 (BTO10/STO10) were fabricated on STO(001) substrate by the molecular beam epitaxy method (MBE), and the molecular layers of SrRuO3(SRO) was introduced into these superlattices as conductive layers. The superlattices introduced two conductive layers showed the enormous dielectric permittivity. On the other hand, the permittivity of the superlattice introduced one conductive layer was almost same as that of BTO10/STO10. In the case of introducing two conductive layers, the moving electrons between two layers induced the interfacial polarization. Especially, the superlattice with two SRO conductive layers, the distance between these layers in a superlattice is 18 molecular layers, showed the highest relaxation frequency 132 kHz and biggest capacitance.

Abstract: Recent progress in the growth of nitride based semiconductor structures made by plasma assisted MBE (PAMBE) is reported. The technology is ammonia free and the nitrogen for growth is activated by an RF plasma source from nitrogen molecules. A new approach for the growth of nitrides by PAMBE at temperature range 500 - 600°C is described. The key for this technique is to use a thin, dynamically stable metal (In or Ga) layer on the (0001) GaN surface, which enables a high quality 2D step-flow growth mode to be achieved at temperatures much lower than those determined by thermodynamic considerations. A new perspective for PAMBE in optoelectronics has been opened recently by a demonstration of continuous wave operation of InGaN blue–violet laser diodes. These laser diodes were fabricated on bulk GaN substrates with a low threading dislocation density.

Abstract: Synchrotron radiation photoemission spectroscopy was used to study the initial growth of Er2O3 films on Si in O2 pressures of 7×10-6 Torr. An interface layer was observed at the initial growth of Er2O3 film on Si, which is supposed to be attributed to the effect of the Er atom catalytic oxidation effect. With the film growth process continued, oxygen deficient Er oxide will capture oxygen from the interface layer which is formed inevitably at the initial growth of Er2O3 film and thus reduce and even remove the interface layer if the condition of O2 pressure is a little insufficient at a high substrate temperature.