Conformality of a-Si:H deposited by low temperature PECVD for solar cells application

This work is devoted to the study of the deposition of a-Si:H by the PECVD method in continuous and pulsed regime on test structures in the form of trenches with a high aspect ratio. The thicknesses of the layers obtained in these modes were investigated by the method of scanning electron microscopy. It was shown that the layers obtained in the pulsed mode, as compared with the continuous one, have better conformity.

Ytterbium-doped fiber laser as pulsed source of narrowband amplified spontaneous emission

We report random noise pulsed regime of an ytterbium-doped fiber laser arranged in common Fabry-Perot configuration. We show that the laser output obeys the photon statistics inherent to narrowband amplified spontaneous emission and that the noise pulsing is properly addressed in terms of probability density and autocorrelation functions. Our novel approach reveals, in particular, that the regime’s coherence time dramatically shortens, from few ns to tens ps, with increasing laser power.

Инжекционные лазеры InGaAlP/GaAs оранжевого оптического диапазона (~600 нм)

Lasing in orange spectral range(599−605 nm)in(AlxGa1−x)0.5In0.5P−GaAs laser diodes grown by MOVPE on GaAs substrates(211) and (322) was demonstrated. The active region consisted of 4 layers of InxGa1−xP vertically coupled quantum dots. Carrier leakage from the active area was suppressed by using barriers formed with 4 quantum-sized layers of InGaAlP with high Ga content. The maximum optical power in the pulsed regime was limited by catastrophic optical mirror degradation and reached 800 mW. Lower threshold current density, higher differential efficiency, and lower internal losses were demonstrated by lasers processed from epitaxial structures grown on(322)A substrates in comparison to those grown on(211)A. This fact is due to the higher energy barrier for electrons in the first case.