Silicon-based light-emitting transistor with Ge(Si) nanoislands embedded in a photonic crystal: Control of the spectrum and spatial distribution of the emission

Light-emitting transistors (LETs) represent the next step in the development of light-emitting diodes (LEDs), offering additional control over emission. In this work, the transport properties and spatial distribution of electroluminescence (EL) in the spectral range of 1.2–1.7 μm were studied for lateral p+-i-n+ LEDs based on silicon-on-insulator structures with self-assembled Ge(Si) islands embedded in photonic crystals. It is shown that due to the low mobility of holes and their effective trapping in the islands, the maximum EL yield is observed at the i/p+ junction of the LED. It is demonstrated that the sign and magnitude of the bias voltage applied to the substrate (to the gate) have a significant influence on the transport and emission properties of the LEDs with Ge(Si) islands, turning them into LETs. In particular, applying a negative gate voltage shifts the position of the maximum emission region from the i/p+ to the i/n+ junction of the LET, which is related to the formation of a hole conductivity channel near the buried oxide layer. The embedding of a specially designed photonic crystal in the i-region of the LET makes it possible to manage the spectral properties of the near-IR emission by changing the sign of the gate voltage. The results obtained may be useful for the future development of optoelectronic devices.