LP-MOCVD growth and characterization of undoped and modulation doped GaInAsP/InP and GaInAs/InP multi quantum wells

Abstract We report on the characteristics of GaInAs/InP and GaInAsP/InP MQW structures grown by low pressure MOCVD at 20 mbar using TMI, TMG, AsH 3 and PH 3 . High gas velocities and gas switching valves with minimized dead space permit the deposition of very uniform films and abrupt interfaces and doping profiles. Analysis of the structures was performed by PL (2K) (6 to 300 K), magnetotransport (4.2 K) and photoconductance (10 to 300 K) measurements. large PL line shifts and very narrow line widths are observed for GaInAs and GaInAsP QWs. A detailed study by magnetotransport and Hall measurements of the 2DEG in GaInAs(P)/InP modulation doped structures reveals the contribution of different scattering mechanisms. The photoconductive response of undoped and modulation doped GaInAs(P)/InP MQWs permits identification of subband levels and allows calculation of the conduction band offset. Photoconductivity is negative at low T , which shows that coulomb scattering by photoexcited minority carriers trapped in the well dominates. The data show that the structures exhibit low impurity content at the interface and that highly reproducible growth is feasible at low pressure.