REALIZATION AND ANALYSIS OF GAAS/ALAS/IN0.1GA0.9AS BASED RESONANT TUNNELING DIODES WITH HIGH PEAK-TO-VALLEY RATIOS AT ROOM-TEMPERATURE

Investigations of pseudomorphic resonant tunneling diodes based on the GaAs/AlAs/In0.1Ga0.9As material system reveal that the use of undoped In0.1Ga0.9As spacer layers gives rise to a significantly enhanced peak-to-valley ratio of 3.2 and 14 at 300 and 77 K, respectively, as opposed to 2 and 5 obtained with the use of conventional GaAs spacers in an otherwise identical structure. This is achieved without any significant degradation of the peak current density but rather through reduction of the undesired nonresonant valley current. Comparison of the experimental results with calculations done using the Airy function transfer matrix approach indicates that the Γ-X discontinuity at the GaAs/AlAs and In 0.1Ga0.9 As/AlAs interface is relevant for electron tunneling, along with the smaller transverse effective mass of 0.19m0 in the AlAs X valley. We also find that In0.1Ga0.9As layers grown under an excess As-stabilized growth condition give better results than those grown under a barely As-stabilized condition.