Low threshold voltage blue light emitting diodes based on thulium doped gallium oxides

Thulium doped gallium oxides (Tm-Ga2O3) films were deposited on Si substrates by the pulsed laser deposition method. Blue emissions (476 nm and 460 nm) can be observed by the naked eye from Tm-Ga2O3/Si light emitting diodes (LEDs). The threshold voltage of Tm-Ga2O3/Si LEDs is 6.3 V, which is lower than that of Tm-GaN/Si devices. By combining our previously reported green emission from Er-Ga2O3 and red emission from Eu-Ga2O3, strong blue emission from Tm-Ga2O3 can realize the full-color LEDs with the single host of Ga2O3. These results open a pathway for integrating Ga2O3 based full-color LEDs with mainstream Si technology.