Nitride based semiconductor light-emitting device

Abstract

Disclosed herein is a nitride-based semiconductor light-emitting device. The nitride-based semiconductor light-emitting device comprises an n-type clad layer made of n-type Alx1Iny1Ga(1−x1−y1)N (where 0≦x1≦1, 0≦y1≦1, and 0≦x1+y1≦1), a multiple quantum well-structured active layer made of undoped InAGa1−AN (where 0<A<1) formed on the n-type clad layer, and a p-type clad layer formed on the active layer wherein the p-type clad layer includes at least a first layer made of p-type Iny2Ga1−y2N (where 0≦y2<1) formed on the active layer and a second layer made of p-type Alx3Iny3Ga(1−x3−y3)N (where 0<x3≦1, 0≦y3≦1, and 0<x3+y3≦1) formed on the first layer.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a nitride-based semiconductor light-emitting device, and more particularly to a nitride-based semiconductor light-emitting device which employs a p-type clad layer structure with enhanced hole injection efficiency into an active layer, thereby exhibiting a high luminous efficiency. [0003] 2. Description of the Related Art [0004] Generally, nitride-based semiconductor light-emitting devices are optical devices with a high output that generate short-wavelength light in the blue and green ranges and the like, and thus enable realization of the full color spectrum. For these reasons, nitride-based semiconductor light-emitting devices have drawn attention in related industrial fields. [0005] Nitride-based semiconductor light-emitting devices are semiconductor single crystals composed of AlxInyGa(1−x−y)N (wherein 0≦x≦y, 0≦y≦1 and 0≦x+y≦1) which can be grown on substrates, e.g., sapphire an...

AI Technical Summary

Benefits of technology

The present invention provides a nitride-based semiconductor light-emitting device that employs a p-type clad layer structure consisting of an electron blocking layer, an active layer, and a hole injection efficiency-enhancing layer interposed therebetween. This prevents electrons from overflowing and enhances hole injection efficiency. The p-type clad layer includes at least a first layer made of p-type Iny2Ga1−y2N (where 0<x2<1, 0<y2<1, and 0<x3+y3<1) and a second layer made of p-type Alx3Iny3Ga(1−x3−y3)N (where 0<x3<1, 0<y3<1, and 0<x3+y3<1). The first layer has a higher doping concentration than the second layer, and the second layer has a higher hole concentration than a p-type AlGaN layer. The nitride semiconductor layer containing no Al, such as GaN, is interposed between the electron blocking layer and the active layer, preventing electron overflow and enhancing hole injection efficiency.

Problems solved by technology

However, since AlGaN not only has a lower hole mobility than any other nitride semiconductor layers, but also has a relatively low hole concentration (about 1×1017 / cm3), the injection efficiency of holes generated from the p-side electrode 19b to the active layer 15 may be lowered, thus causing a problem in obtaining a high luminous efficiency.

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