It would appear that BLG have discovery a marginal improvement...

It would appear that BLG have discovery a marginal improvement in reduced resistivity by using (lower temperature) RPCVD to deposit the p-GAN when producing a conventional laser diode and then (presumably a greater improvement) by inserting a buried tunnel junction and using n-GaN on the upper surface (at the cost of greater complexity) of the laser diode. I would assume that using RPCVD to deposit the p-GAN is unlikely to increase costs significantly and could be a "mid life kicker" for the BLG laser diode but it's still unstated as to whether the target of an improved conversion efficiency for the tunnel junction laser diode is worth the additional complexity. It would be good to see something from BLG that showed the improvement in conversion efficiency against the increased costs of fabrication.

You often get the situation where an improvement is possible but the business case does not stack up; I would welcome something on the business case for tunnel junction laser diodes rather than just quoting the potential for improvement without an indication of the entailed additional fabrication costs (and also a bit more on the timescale for deliveries of the tunnel junction laser diode and also the RPCVD lower resistivity laser diode).