Optical and electrical characterization of quantum dot infrared photodetector structure treated with hydrogen-plasma

Abstract

We have carried out hydrogen-plasma (H-plasma) treatments on a quantum dot infrared photodetector (QDIP) structure, with a 5-stacked InAs dots in an InGaAs well structure and a Al0.3Ga0.7As/GaAs superlattice barrier. The sample structures were grown by molecular beam epitaxy. The H-plasma treatment has been carried out at 150 degrees C for 3 min - 40 min with 40 sccm of H-2 gas flow rate and 10 W of RF power. After H-plasma treatment, photoluminescence (PL) intensities of the samples were slightly reduced compared to that of as-grown sample, without any changes in their PL peak position. The dark currents of H-plasma treated samples were much smaller by many orders of magnitudes than that for as-grown sample. ne sample exposed to H-plasma for 10 min showed the lowest dark current, enabling the observation of photocurrent with a wide spectrum between 3 - 12 mu m at 11 K.