Real-space transfer (RST) light-emitting transistors are implemented with a strained GaAs/InGaAs/GaAs quantum well heterostructure fabricated on GaAs substrates. The device energy band diagrams are simulated by using the MEDICI program. Two optical measurements, electroluminescence (EL) and photocurrent, are performed to characterize the RST light-emitting transistors. The RST of hot electrons into the active region is measured by EL at 77 K. The light emitted from the RST device is detected by a separate photodetector and the photocurrent is found to be consistent with the RST current-voltage(IC−VD)characteristics. The 77 K EL emission peak wavelength is about 9000 Å. The EL spectra confirm that the emission is dominated by emission from the GaAs/InGaAs/GaAs quantum well. AtVD=0 V, the EL emission intensity due to hole leakage current is about 2 orders of magnitude lower than that of the electron leakage current. ©1997 American Institute of Physics.