Optically pumped InGaN/GaN double heterostructure lasers with cleaved facets

Ultrawide‐Bandgap Semiconductors: Research Opportunities and Challenges

“…InGaN optoelectronics technologies are unique in that they have succeeded despite their common use of non-lattice-matched foreign substrates (such as sapphire and SiC) and the resulting high (≈10 8 cm −2 ) defect densities. [33,34] However, even these now-ubiquitous InGaN optoelectronics technologies improve markedly when they make use of low-defect-density single-crystal GaN substrates. We cannot discount the possibility that AlGaN technologies could be developed with similarly good performance on non-lattice-matched foreign substrates, despite high defect densities.…”

Lasing and longitudinal cavity modes in photo-pumped deep ultraviolet AlGaN heterostructures

“…Above the lasing threshold, both structures showed slope efficiency comparable to that of InGaN-based lasers. 20 Figure 2 shows the high-resolution lasing spectra with different integration times for the two structures. Due to the lack of proper laser sources in the deep UV spectral range, excimer lasers are widely used as excitation sources for many optical measurements.…”

Crystallographic wet chemical etching of GaN

“…[7][8][9][10] PEC etching has the advantage of relatively low equipment cost and low surface damage, but a method for producing smooth vertical sidewalls has not yet been found. Cleaved facets for GaN have also been reported, with rms roughnesses varying between 16 nm for GaN grown on sapphire substrates 11 and 0.3 nm for GaN grown on spinel substrates. 12 While KOH-based solutions have been found to etch AlN and InAlN, no acid or base solution has previously been identified that is able to etch high-quality GaN.…”