Semiconductor laser diode with low threshold current

Abstract

A group III nitride based laser light emitting device includes an n-side group III nitride based semiconductor region, a p-side group III nitride based semiconductor region, and a group III nitride based active region between the p-side group III nitride based semiconductor region and n-side group III nitride based semiconductor region. The group III nitride based active region includes first andsecond quantum well layers and a barrier layer between the first and second quantum well layers, the respective compositions of the first and second quantum well layers comprising different respectiveamounts of indium. The first quantum well is closer to the n-side group III nitride based semiconductor region than the second quantum well, the second quantum well is closer to the p-side group IIInitride based semiconductor region than the first quantum well, and the first quantum well has a larger band gap than the second quantum well.

Description

technical field [0001] The invention relates to the epitaxial structure of semiconductor laser diodes, especially the active region structure of Group III nitride-based semiconductor laser diodes. Background technique [0002] Laser diodes (LDs) based on III-nitride semiconductors are commercially available with emission wavelengths in the UV, blue and green portions of the electromagnetic spectrum. Such devices are used in applications such as lighting and display. It is especially important to provide such devices with high optoelectronic performance. [0003] Group III nitrides (or nitrides) based on GaN and alloys containing In and Al (hereinafter referred to as (Al,In,Ga)N alloys) can be fabricated to form high-efficiency LD devices. The semiconductor layer structure of such devices can be fabricated by sequentially forming semiconductor layers on a substrate. These layers are physically connected and are usually of high crystalline quality obtained by using epitaxia...

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Problems solved by technology

This can be achieved by reducing the concentration of dopant species in these layers, however these species can negatively affect hole injection from the p-side semiconductor region and the n-side semiconductor region into the active region

[0020] III-nitride-based semiconductor laser diodes by improving carrier injection and carrier uniformity into the active region while maintaining strong light confinement and high crystallographic quality without degrading the characteristics of the emitted laser light The problem of the threshold current reduction of the

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