Auger Recombination in Quantum - Well InGaAsP Heterostructure Lasers

Interband nonradiative Auger recombination in quantumwell InGaAsP/InP heterostructure lasers has been calculated. It is found that the Auger rate is much reduced in the quasi two-dimensional quantum-well lasers. This suggests that the temperature sensitivity of quantum-well InGaAsP lasers is much less than ordinary structures with much higher values of To at around room temperatures. A CONTINUING problem with lasers and light emitting diodes (LED) based on the quaternary compound In,-,Ca,AsyP1-y lattice matched to InP is their temperature sensitivity. In LED’s, the optical output power saturates at high current densities and, in lasers, the threshold current increases rapidly with temperatures above 220-250 K. In the case of lasers, the threshold current has been found empirically to vary with temperature T as Ith exp (T/To). The quantity To determines the temperature sensitivity of the device. In InGaAsP lasers, the log (Ith) versus T plot exhibits a break-pomt temperature below which the To is typically about 110 K, whereas above the break-point temperature, To has a low value of -50-60 K [I]-[3]. The break-point typically occurs at around 220-250 K. The To in GaAlAs/GaAs lasers, on the other hand, remains at about 120-170 K over the same temperature range [4]. Many mechanisms have been proposed to account for the low To of the quaternary lasers. Among the various mechanisms considered, the interband Auger recombination has been found to be a dominant factor Although itas been demonstrated that GaAlAs/GaAs quantum-well lasers exhibit higher To’s [8], it is unclear whether InGaAsP quantum-well lasers would be free from a break-point in the threshold current versus temperature characteristics. In this paper, we present an analysis of the nonradiative Auger recombination in the quantum-well lasers. I t is found that the rate of Auger recombination is greatly reduced in such quasi two-dimensional structures. It is thus suggested that the log (Ith) versus T plot for such lasers would be free from a low temperature break-point and the To for temperatures above 220-250 K should remain above 120 IC. Experimental confirmation of this prediction will also serve as a check on the importance of Auger recombination in ordinary InGaAsP lasers. The data in [9] for multiple quantum-well lasers do indicate that the breakpoint is -300 K, which is considerably higher than ordinary quaternary lasers. PI v i . Manuscript received April 5, 1982;revised June 11, 1982. This work was supported by the Office of Naval Research and the Air Force Office of Scientific Research. The authors are with the California Institute of Technology, Pasadena, CA 91125. AMNON YARIV