Semiconductor light-emitting device using graded multi quantum barrier

• US 20030197188A1
• Filed: 12/19/2002
• Published: 10/23/2003
• Est. Priority Date: 04/23/2002
• Status: Active Grant

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Watatani, Chikara, Hanamaki, Yoshihiko
• Granted Patent: US 6,803,597 B2
• Time in Patent Office: Days
• US Class Current: 257/88
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: H01L 33/04 with a quantum effect structure or superlattice, e.g. tunnel junction
• CPC Class Codes: H01L 33/06 within the light emitting region, e.g. quantum confinement structure or tunnel barrier
• CPC Class Codes: H01S 5/2013 MQW barrier reflection layers
• CPC Class Codes: H01S 5/3215 graded composition cladding layers
• CPC Class Codes: H01S 5/3216 quantum well or superlattice cladding layers
• CPC Class Codes: H01S 5/3409 special GRINSCH structures
• CPC Class Codes: H01S 5/343 in AIIIBV compounds, e.g. AlGaAs-laser , InP-based laser

Abstract

In a semiconductor light-emitting device, an active layer has a multi quantum well structure (MQW) that a plurality of barrier layers and a plurality of quantum well layers are alternately arranged. Each of the cladding layers has a multi quantum barrier structure (MQB) that a plurality of barrier layers and a plurality of well layers are alternately arranged. A configuration of the multi quantum barrier (MQB) of each of the cladding layers varies in a graded or stepwise form. Thus, carriers are suppressed from overflowing from the active layer, preventing cut-off of a guided wave mode, increasing a reflectance of electrons entering the energy barriers and improving a temperature characteristic.

Claims

1. A semiconductor light-emitting device comprising:

an active layer for generating a light, the active layer having a multi quantum well structure in which a plurality of barrier layers and a plurality of quantum well layers are alternately arranged; and

a pair of cladding layers which sandwiches the active layer to confine the light within the active layer,

wherein each of the cladding layers has a multi quantum barrier structure in which a plurality of barrier layers and a plurality of well layers are alternately arranged, and wherein the multi quantum barrier layers of each of the cladding layers are graded in configuration.

2. The semiconductor light-emitting device according to claim 1, wherein energy band gaps of the barrier layers in the multi quantum barrier structure are varied stepwise.

3. The semiconductor light-emitting device according to claim 1, wherein energy band gaps of the well layers in the multi quantum barrier structure are varied stepwise.

4. The semiconductor light-emitting device according to claim 1, wherein the multi quantum barrier structures of said paired cladding layers sandwiching the active layer are different in configuration and asymmetric in structure.

5. The semiconductor light-emitting device according to claim 1, wherein said cladding layer comprises a multi quantum barrier subjected to partial doping, and the partial doping is a modulation doping performed only for the barrier layers, well layers, a part of the barrier layers or a part of the well layers.

6. The semiconductor light-emitting device according to claim 1, wherein in the multi quantum well structure of said active layer, a width and configuration of each of the quantum well layers are optimized such that quantum levels contributing to light emission are constant over the entire quantum well layers, and that an energy band gap of a quantum well layer in the vicinity of the cladding layer is smaller than that of a quantum well layer at a central portion of the active layer.