Overcoming the current injection issue in the 310 nm band AlGaN UVB light-emitting diode. (21st November 2019)

• Record Type: Journal Article
• Authors: Khan, M. Ajmal; Matsuura, Eriko; Kashima, Yukio; Hirayama, Hideki
• Is Part Of: Japanese journal of applied physics. Volume 59:Number SA(2020)
• Publication Date: 2019-11-21
• Subjects: Physics -- Periodicals; 621.05
• DOI: 10.7567/1347-4065/ab460b
• Languages: English
• ISSNs: 0021-4922

Abstract

Abstract: AlGaN-based ultraviolet-B (UVB) LEDs at 310 nm emissions are expected to offer safe and smart size UVB-light sources compared to the toxic mercury UV-lamp. Previously, the issue of nonlinearity in the emitted light output power ( L ) as well as in the external quantum efficiency (EQE) of 310 nm band UVB LEDs were observed. First, the influence of both the number of n-AlGaN buffer layers (BLs) and the type of p-electrodes on the recovery of linear behavior in the L and EQE were investigated. It was found that the nonlinearity in the L and EQE of UVB LED is independent of the number of BLs as well as type of p-electrodes. Therefore, finally the dependence of nonlinearity in the L and EQE on the thickness of quantum-well-barrier ( T QWB ) of multi-quantum-wells (MQWs) were also considered. Subsequently, the issue of nonlinear behavior in the L and EQE was resolved by the thickness reduction of T QWB from 25 to 10 nm in the MQWs. Similarly, a reasonable value of improvement in both L and EQE, respectively, up to 12 mW and 2.2% of 310nm band UVB LED were realized.