Double heterostructure lasers prepared by LPE on medium-quality GaAs substrates under controlled as vapour conditions

The fact that defect formation in (Ga, Al)As LPE layers can be suppressed by the presence of arsenic vapour is employed to improve properties of double heterostructure (DH) lasers. The controlled vapour pressure (CVP) method is implemented using a modified LPE horizontal carbon boat. Growth kinetics study under near-equilibrium conditions shows that the presence of arsenic vapour diminishes the growth rate of aluminium-containing layers; no such influence has been observed with the GaAs layers. The CVP method, compared with the customary LPE, has a beneficial effect on the DH surface and cross sections perfection, as well as on the lasing characteristics (differential quantum efficiency, threshold current). Observed values of the parameter T₀, characterizing temperature dependence of the laser threshold current, fall into the vicinty of 200 K. The results have been obtained on medium-quality GaAs substrates.