Very strong negative differential resistance real-space transfer transistor using a multiple δ-doping GaAs/InGaAs pseudomorphic heterostructure

We present the observation of an effective real-space transfer process of hot electrons resulting in a very strong negative differential resistance in GaAs/In_0.25Ga_0.75As/GaAs pseudomorphic heterostructure by growing symmetrically double δ-doping layers on both sides of the InGaAs channel. By Hall measurements, the proposed structure shows carrier mobility as high as 4500 (14 100) cm²/V s at 300 (77) K which is suitable for high-frequency operations. Meanwhile, this structure with a 5×100 μm² emitter channel reveals extremely sharp charge injection, broad current valley range (>3 V), high transconductance (over 23.5 S/mm), high current driving capability, and high peak-to-valley current ratio (up to 156 000). We also carried out secondary-ion mass spectrometry profiles to confirm the quality of the proposed structure.