Light-emitting transistor based on real-space transfer: electrical and optical properties

The charge injection transistor is implemented in InGaAs/InAlAs/InGaAs heterostructure material, grown by molecular beam epitaxy. A complementary collector of p-type conductivity is used for the first time. The real-space transfer of hot electrons leads to a luminescence signal proportional to the injection current. The radiative efficiency is significantly enhanced by a double-heterostructure design of the collector active region, which confines the injected minority carriers. The internal quantum efficiency of the light-emitting transistor is comparable to that of light-emitting diodes. Due to peculiar symmetry of real-space transfer, the optical output signal follows an exclusive-OR function of input voltages. Functional logic operation of the device is demonstrated at room temperature.>