PAM-XIAMEN offers 950nm InGaAs quantum well laser diode wafers. In the application of optoelectronic devices, the InGaAs / GaAs strained quantum well (QW) structure is one of the research hotspots, and the emission band of the InGaAs / GaAs strained quantum well covers the band gap (880~1100nm) between the GaAs and InP material systems. AlGaAs / InGaAs laser diode structure by MOCVD or MBE from PAM-XIAMEN is specifically as follows:
1. InGaAs Laser Diode Epitaxial Structure on GaAs Substrate
950nm LD wafer parameters are listed in table:
|LD Wave Length (nm)||950|
|Wafer PL or EL (nm)||935+-5nm|
|PL Uniformity (6mm edge exclude)||+-2nm|
|XRD (for thick layers)||–|
|LD Slop Efficiency with AR + HR Coating (W/A)||>1.05|
2. Characteristics of InGaAs / AlGaAs Laser Epitaxial Structure
The <100> dark line defect has a high growth rate in GaAs quantum well lasers, but is suppressed in InGaAs quantum well lasers. The reason for this is that since In atoms are larger than Ga, Al and As atoms, the propagation of defects is hindered and acts as a dislocation blocker. In addition, compared with AlGaAs / GaAs laser, InGaAs laser diode has better performances:
(1) Less energy released by radiative and non-radiative recombination;
(2) The InGaAs / GaAs interface has less nonradiative recombination centers than the AlGaAs / GaAs interface;
(3) GaAs substrates are transparent to wavelengths above 900 nm, thus reducing the rate of defect reactions such as diffusion, dissociation, and annihilation due to recombination enhancement.
In addition, it can widen the wavelength (λ) of the laser to the range of 880nm≤λ≤1100nm by adjusting the In composition and well width. So InGaAs laser diode pumping is widely used in new laser devices. By frequency doubling, InGaAs-AlGaAs single-mode laser structure can be used as a blue-green laser. Due to the increased discontinuity of the conduction band caused by the strain of the epitaxial layer, the Auger recombination is reduced, so that the operating temperature of the diode laser can be as high as 180 °C.
3. Laser Diode Arrays with InGaAs Strain Quantum Well
When InGaAs is grown on GaAs, the maximum lattice mismatch can reach 7% to form a strained quantum well. In the strained layer quantum well structure, the difference between the two highest heavy hole energy levels can be controlled by changing the well width, and the difference between the highest heavy holes and the highest light holes can be controlled by controlling the axial strain. The thickness of the GaAs / InGaAs quantum well can affect the crystal structure, that is, the energy band changes through the action of stress, which makes the device design more flexible, which is beneficial to improve the device performance and design functional devices. The GaAs / InGaAs strained layer structure has been widely used in high-frequency high-speed devices and strained layer quantum well lasers.
Using MBE growth technology, an InGaAs strained layer quantum well laser with a threshold current density as low as 50A/cm2 has been developed. The InGaAs laser diode has many excellent properties, such as low threshold current, narrow spectral width, high polarization ratio, tunable, weak temperature dependence and high relaxation oscillation frequency, etc.