Effect of Si doping in AlAs barrier layers of AlAshyphen;GaAshyphen;AlAs doublehyphen;barrier resonant tunneling diodes

摘要

AlAshyphen;GaAshyphen;AlAs doublehyphen;barrier resonant tunneling diodes (DBRTDs) with different doping levels in the AlAs layers have been investigated. Twohyphen;step spacer layers were used in all samples. Peakhyphen;tohyphen;valley current ratios (PVCRs) as high as 3.5 (11.3), 3.5 (11.3), and 2.7 (8.2) were observed at 300 K (77 K) for samples with undoped, 1.2times;1017cmminus;3, and 3times;1018cmminus;3doped AlAs barriers, respectively. These results indicate that resonant tunneling is not strongly affected by ionized Si atoms in the AlAs barriers. The excellent PVCRs observed in DBRTDs with twohyphen;step spacer layers is not because of low background impurity densities in the active region, but because of a third barrier formed by band bending in the spacer layers.