We propose a way of increasing overall efficiency of InGaN-GaN ultraviolet light-emitting diodes (UV LEDs) by placing a thin Si-doped AlGaN layer beneath the multiple quantum well (MQW). The AlGaN thin layer plays a role of tunneling barrier for the electrons, making a low-energy electron injection possible. The effect of the AlGaN thin film is verified by the simulation regarding the carrier distributions. By using this idea, the overall efficiency of the UV LED is enhanced by 13.5% over that of the conventional UV LEDs. (C) 2004 Elsevier B.V. All rights reserved.