Publications by authors named "ZengCheng Li"
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 Synopsis
- Silicon photonics has been seeking efficient on-chip light sources that can be electrically driven at room temperature, particularly microdisk lasers due to their directional lasing capabilities.
- Traditional challenges in developing III-nitride microdisk lasers on silicon have included issues with material quality and undercut structures, hindering progress.
- Recent advances have led to the successful creation of electrically pumped InGaN-based microdisk lasers on silicon, demonstrating clear signs of lasing, marking a significant step forward in this technology.
A Study of Efficiency Droop Phenomenon in GaN-Based Laser Diodes before Lasing.
Materials (Basel)
April 2017
Carrier recombination behavior in c-plane GaN-based laser diodes (LDs) is numerically investigated by using the commercial software LASTIP. It is found that efficiency droop phenomenon does exist in GaN-based LDs before lasing, which is confirmed by experimental results. However, the current density corresponding to the peak efficiency of GaN-based LDs before lasing, J, is nearly 40 A/cm², which is much lower than that reported by other studies.
View Article and Find Full Text PDFSemiconductor vertical-cavity surface-emitting lasers (VCSELs) with wavelengths from 491.8 to 565.7 nm, covering most of the 'green gap', are demonstrated.
View Article and Find Full Text PDFBy observing the morphology evolution of green InGaN/GaN quantum well (QW) and studying the catholuminescence (CL) property, we investigate indium-segregation-related defects that are formed at green InGaN/GaN QW interfaces. Meanwhile, we also propose the approach and suggest the mechanism to remove them for green InGaN/GaN QW grown on both GaN templates and free-standing GaN substrates. By engineering the interface of green InGaN/GaN QWs, we have achieved green laser diode (LD) structure with low threshold current density of 1.
View Article and Find Full Text PDFLow threshold continuous-wave (CW) lasing of current injected InGaN quantum dot (QD) vertical-cavity surface-emitting lasers (VCSELs) was achieved at room temperature. The VCSEL was fabricated by metal bonding technique on a copper substrate to improve the heat dissipation ability of the device. For the first time, lasing was obtained at yellow-green wavelength of 560.
View Article and Find Full Text PDFStrong localization effect in self-assembled InGaN quantum dots (QDs) grown by metalorganic chemical vapor deposition has been evidenced by temperature-dependent photoluminescence (PL) at different excitation power. The integrated emission intensity increases gradually in the range from 30 to 160 K and then decreases with a further increase in temperature at high excitation intensity, while this phenomenon disappeared at low excitation intensity. Under high excitation, about 40% emission enhancement at 160 K compared to that at low temperature, as well as a higher internal quantum efficiency (IQE) of 41.
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