Real index-guided AlGaInP visible laser with high-bandgap energy AlInP current blocking layer grown by HCl-assisted metalorganic vapor phase epitaxy

Realization of real index-guided InGaAlP red lasers with buried tunnel junctions

“…Large internal loss contributes to the high threshold current and low slope efficiency of conventional complex index-guided lasers. It is believed that the relatively low internal loss in our work compared with in previous reports 3,5 could be due to the good material quality of the In 0.5 Al 0.5 P regrown layers.…”

“…Second, the regrown In 0.5 Al 0.5 P layers with larger band gap form the real index-guiding structure and reduce internal loss. Last, this buried tunnel junction laser requires only one step regrowth compared to the two step regrowth reported by Kobayashi et al 3,4 In the present work, the n-type In 0.5 Al 0.5 P layers that serve as lateral optical guiding can be regrown directly after the formation of laser ridges by conventional MOCVD. The buried tunnel junctions located on top of the laser ridges serve as window areas and assist current flowing from p-type cladding layers to n-type In 0.5 Al 0.5 P layers and then to top n-contact layers.…”

“…However, it has been difficult to selectively grow In 0.5 Al 0.5 P layers by conventional metalorganic chemical vapor deposition ͑MOCVD͒. Kobayashi et al reported real index-guided InGaAlP lasers grown by HCl-assisted MOCVD, 3,4 in which the In 0.5 Al 0.5 P layers was selectively regrown. Imafuji et al reported a real refractive index-guided self-aligned structure by regrowning the InGaAlP laser ridges.…”