Effect of AIGaAs cladding layer on GaInNAs/GaAs MQW p-i-n photodetector

摘要

The electronic properties of GaInNAs/GaAs multiple-quantum-well (MQW) p-i-n photodetector with AIGaAs cladding layer have been studied. By applying a higher band gap Alo.3Gao.7As to the photodetector, a substantial reduction in dark current was observed owing to an inherent difficulty for holes to surmount the high potential barrier between MQW and the cladding layer heterojunction under a reverse bias. The dark current obtained was as low as 4.1 pA at -3.5 V for a device with Alo.3Gao.7As cladding layer as compared to 22 uA also at -3.5 V for a similar device without thernAlo.3Gao.7As cladding layer. The photo/dark current contrast ratios obtained were 4.2×10~4 and 11, respectively, for devices with and without an Al_(0.3)Ga_(0.7)As cladding layer at -3.5 V. In addition, peak responsivity of 1 mA/W was measured at around 1150 nm. Two orders of magnitude increase in the rejection ratio were realized between 1150 and 1250 nm at -2.0 V. The GaInNAs/GaAs MQW p-i-n photodetector was demonstrated with the AIGaAs cladding layer potentially providing a higher photo/dark current contrast ratio and higher responsivity rejection ratio.