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The AlGaN-based deep ultraviolet (DUV) light-emitting diodes (LEDs) with p-hBN layer are investigated numerically. In comparison with the conventional AlGaN DUV LEDs, the proposed LED can significantly improve the carrier injection, radiative efficiency, as well as the electroluminescence (EL) intensity under the same applied forward bias. Simultaneously, the light extraction efficiency in the LED using p-hBN instead of p-AlGaN exhibits a more than 250% increase at the applied voltage of 7.5 V due to the smaller loss of reflection and absorption of the emitted light. [ABSTRACT FROM AUTHOR]

Abstract: The AlGaN-based deep ultraviolet light-emitting diodes (UV LEDs) with specific design of staggered AlGaN quantum wells are investigated numerically. The proposed UV LEDs with Al0.45Ga0.55N–Al0.5Ga0.5N–Al0.45Ga0.55N and Al0.5Ga0.5N–Al0.45Ga0.55N–Al0.5Ga0.5N staggered quantum well layers exhibit significant improvement for the light output power and carrier injection efficiency compared with the conventional AlGaN UV LED. The enhanced performance of the designed LEDs is explained by the simulated distribution of carrier concentration, radiative recombination rate and wave function overlap in the quantum wells. [Copyright &y& Elsevier]

Abstract: Selective area epitaxy has been applied to grow GaN stripe templates with side facts, followed by InGaN/GaN multiple quantum well (MQW) structures. Stripes oriented along the direction of [11−20] form smooth triangular {1−101} facets, while stripes in the [1−100] direction produce incomplete coalesced {11−22} side facets with planar (0001) surface under the same growth conditions. Room-temperature luminescence property is investigated by using photoluminescence (PL) and cathodeluminescence (CL) spectra. It is found that uniform emission at 400nm has been obtained for triangular MQWs oriented the direction of [11−20]. With respect to the MQWs grown along the [1−100] direction, large redshift is achieved for the ridge area compared to the sidewall due to the lateral vapor diffusion and surface migration. [Copyright &y& Elsevier]

Abstract: Structural and optical properties of a-SiN x films deposited by electron cyclotron resonance chemical vapor deposition (ECRCVD) have been investigated. The Fourier transform infrared (FTIR) spectroscopy shows the structural evolution of the SiN x films, which are defined as Si-rich SiN x and N-rich SiN x films, also confirmed by Raman spectroscopy. The origin of the light emission for SiN x films may be attributed to two mechanisms, i.e., quantum confinement effect (QCE) and transition of defect energy levels. The correlation between light emission and structures of SiN x films is discussed. [Copyright &y& Elsevier]