CHEMICAL BEAM EPITAXY OF GAINASP FOR LONG-WAVELENGTH LASERS

The precise control of growth parameters in chemical beam epitaxy (CBE ) is essential for high-quality photonic devices and monolithic integr ation in OEICs. We find a very narrow growth window suitable for high- quality GaInAsP. We observe a strong dependence of crystal quality fro m the V/III ratio at a growth temperature of 543 degrees C. For GaInAs P with a band gap of 0.95 eV (lambda = 1.3 mu m) a miscibility gap occ urs at this temperature. The material quality is demonstrated by very narrow photoluminescence linewidths of 3-5 meV at 4.2 K for (GaIn)(AsP ) layers of varying compositions. Laser diodes grown under the optimis ed conditions without growth interruptions show very low threshold cur rent densities of 62 A cm(-2) per QW for 10 QWs. Internal losses can b e reduced by using tensile-strained barriers. (C) 1998 Elsevier Scienc e B.V. All rights reserved.