AI Article Synopsis
- Current blue laser diodes (LDs) are typically made from expensive blue laser technology on GaN substrates, limiting their size and cost.
- Using larger and cheaper silicon (Si) substrates for growing indium gallium nitride/gallium nitride (InGaN/GaN) structures can significantly reduce expenses and expand their use.
- A new technique involving AlN/AlGaN buffer layers and optimized growth conditions has allowed the successful creation of a blue LD on Si, achieving notable performance at room temperature.
Article Abstract
Current laser-based display and lighting applications are invariably using blue laser diodes (LDs) grown on free-standing GaN substrates, which are costly and smaller in size compared with other substrate materials. Utilizing less expensive and large-diameter Si substrates for hetero-epitaxial growth of indium gallium nitride/gallium nitride (InGaN/GaN) multiple quantum well (MQW) structure can substantially reduce the cost of blue LDs and boost their applications. To obtain a high crystalline quality crack-free GaN thin film on Si for the subsequent growth of a blue laser structure, a hand-shaking structure was formed by inserting Al-composition step down-graded AlN/AlGaN buffer layers between GaN and Si substrate. Thermal degradation in InGaN/GaN blue MQWs was successfully suppressed with indium-rich clusters eliminated by introducing hydrogen during the growth of GaN quantum barriers (QBs) and lowering the growth temperature for the p-type AlGaN/GaN superlattice optical cladding layer. A continuous-wave (CW) electrically pumped InGaN/GaN quantum well (QW) blue (450 nm) LD grown on Si was successfully demonstrated at room temperature (RT) with a threshold current density of 7.8 kA/cm.
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| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6106987 | PMC |
| http://dx.doi.org/10.1038/s41377-018-0008-y | DOI Listing |
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