Analysis of the Thickness Effect of Undoped Electron-Blocking Layer in Ultraviolet LEDs

作者：Lin Wen Yu^*; Wang Tzu Yu; Liang Jia Hao; Ou Sin Liang; Wuu Dong Sing

来源：IEEE Transactions on Electron Devices, 2014, 61(11): 3790-3795.

DOI：10.1109/TED.2014.2356557

• Electron-blocking layer (EBL)
• light-emitting diode (LED)
• Mg diffusion
• simulation
• ultraviolet (UV)

In this paper, the thickness effect of an undoped Al0.23Ga0.77N inserted in the Mg-doped Al0.23Ga0.77N electron-blocking layer (EBL) on the characteristics of the ultraviolet light-emitting diodes (UV-LEDs) was analyzed. The results of secondary-ion-mass spectrometry clearly show that the concentration of Mg back-diffusion from the p-GaN and the Mg-doped EBL decreases with the thickness of an undoped EBL. The radiative recombination rate in the multiple quantum wells (MQWs) can be obviously enhanced after inserting an undoped EBL from the simulated results, and the sample with a 6-nm-thick undoped EBL has the highest radiative recombination rate. It is worth noticing that the hole carrier concentration in the MQWs increases with increasing the thickness of an undoped EBL. The UV-LED possesses 400% enhancement in the output power (at 20 mA) by inserting a 6-nm-thick undoped EBL. The significant enhancement is ascribed to the decrease of nonradiative recombination defects formed by Mg atoms and the increase of hole concentration in the MQWs.

• 出版日期2014-11