In a parallel effort to its development of UV-C light-emitting diodes (LEDs), HexaTech Inc of Morrisville, NC, USA recently demonstrated optically pumped AlGaN-based lasers grown on single-crystalline aluminium nitride (AlN) substrates.
Laser structures fabricated at HexaTech and tested in collaboration with North Carolina State University (NCSU) featured lasing thresholds as low as 85kW/cm2 at wavelengths of 264nm and 280nm. HexaTech says that this not only represents record laser performance but also further validates its AlN substrate platform for UV-C optoelectronic applications.
“Our recent results show convincing evidence of the feasibility of a solid-state UV-C laser,” comments Dr Andy Xie. "The tests not only demonstrate lasing at low pump intensities, but we also observed emission peak line widths as narrow as 0.02nm, and further tell-tale signs of a properly operating laser, including spectrally resolved cavity modes, TE-mode polarization, and elliptically shaped far-field patterns.”
HexaTech reckons that the observed lasing at low pump intensities is a key milestone toward the development of semiconductor lasers operating at short wavelengths in the UV-C range. Enabled by its low-dislocation-density bulk AlN substrates, the results add to the record UV-C LED and laser performance reported by other groups, the firm comments. The use of high-quality, native AlN substrates that are lattice-matched to the overgrown III-nitride device layers allows the fabrication of optoelectronic devices of superior structural quality and hence previously unachievable performance, HexaTech adds.
There is a growing market opportunity for UV-C lasers used for chemical, biological, and explosive material detection. “HexaTech's core expertise in AlN crystal growth and wafer fabrication has already led to the development of world-class UV-C LEDs with previously unachievable device lifetimes,” claims CEO Joe Grzyb.
Technical details will be published in the scientific literature in the near future.
