Group IV-based optoelectronic devices have been intensively pursued to enable full monolithic Si photonics integration. Such devices have great potential for future needs of compact, low cost, and high -performance. Since group IV semiconductors are inhibited from efficient light emitters due to their indirect bandgap nature, a novel group IV material system, GeSn alloy, has attracted renewed interest. GeSn alloy yields true direct bandgap with Sn incorporation over 8%, and it can be monolithically grown on Si making it desirable for developing a Si-based light source with fully complementary metal-oxide-semiconductor (CMOS) compatibility. Over the past few years, considerable progress has been reported on the development of optically pumped GeSn lasers based on direct bandgap GeSn alloys, f ollowed by the recent demonstration of electrically injected GeSn lasers. In this work, we report the development of electrically injected GeSn laser diodes utilizing GeSn/SiGeSn heterostructures grown on Si substrate, with detailed attention given to the cap layer to reduce the optical loss. The material was fabricated into ridge waveguide laser devices and lasing performance was investigated under pulsed conditions. The collected electroluminescence signa l shows clea r la sing signature, and the L−I characteristics of devices with different cavity lengths were studied at various temperatures. The results provide a route for the improvement of high-performance electrically injected GeSn laser diodes.
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