INVESTIGATION OF SI-DOPED P-TYPE ALGAAS GAAS, ALGAAS/INGAAS QUANTUM-WELL INFRARED PHOTODETECTORS AND MULTIQUANTUM WELLS GROWN ON (311)A GAAS/

We have studied two Si-doped p-type quantum well infrared photodetecto rs (QWIPs) using AlGaAs/GaAs and AlGaAs/InGaAs grown on (3 1 1)A GaAs. The Si-doped AlGaAs/GaAs p-QWIP exhibits a symmetrical dark I-V chara cteristic at all the measured temperatures from 40 to 120 K. The strai ned p-type AlGaAs/InGaAs QWIP exhibits a slightly asymmetrical dark I- V characteristic, but is markedly less asymmetrical than that doped wi th beryllium. The slight asymmetry in dark I-V characteristic and the large blue-shift in responsivity spectra may be due to the thickness m odulation observed from TEM and the red-shift of PL peak energy, where PL peak energies from (3 1 1)A AlGaAs/InGaAs multiple quantum wells a re red-shifts of 7 and 22 meV to the side-by-side grown (1 0 0).