I feel this summary is a bit too pessimistic. Yes progress is not what we would hope - it never is. In my experience commercialization takes about 10 times more resources than production of the initial idea - it's almost always under estimated particularly by developers; nothing peculiar about BLG in this regard, it's life and investors should be aware of this.
BLG (since it was spun off from Macquarie Univ in 2006) has certainly been slow in getting there but since about 2015 does seem to be gaining attention and now has some very credible collaboration partners.
I have been doing a lot of reseach and am now appreciating more the scope of the developments made by BLG in recent years and are becoming more impressed. As I said in my previous post it would appear that the tunnel junction "breakthrough" has some legs to it. If you read the Lumileds patent (see below) this "breakthrough: is the implementation of the Lumileds patent (the description starts about a third of the way through - skip the bureaucratic stuff at the start)
What I find interesting is that the tunnel junction would also appear to have significance not mentioned - see presentation slides below: rajan_droop_raleigh2016.pdf
LEDlights can, in principle, operate at near efficiency level of 100%. Current LED lighting technology is not evenclose to reaching this limit - Lumiled's would have a significant edge on their competition if the employed their patent. Thisis due to several factors. 1. Currentwhite light LED lamps rely on the use of phosphors to down-convert blue lightinto green and red light. Associated with this down-conversion process is anenergy loss of approximately 30%, or more. 2. Theperformance of GaN-based LEDs is limited by inefficient current conduction ofp-GaN, which typically has a resistance of about 100 times higher than that ofn-GaN, leading to poor current spreading, reduced efficiency, and efficiencydroop (LEDs operate most efficiently at low currents of tens of milliamps; however,if the current increases, efficiency tails off (“efficiency droop”). 3. Unlike conventionallight bulbs, LEDs are low-voltage devices and cannot operate on an alternatingcurrent voltage. As a consequence, an electrical circuit is required to convertAC power to low-voltage DC power (typically 2-4V). Such a driver adds asignificant level of complexity, cost, and efficiency loss to the LED devicesand system. Using cascaded LED the voltages are higher (the LED's are in series rather than in parallel). There are designs in use today that allow A/C currents to be used on LED.
Myreading leads me to understand that these problems are largely solved with cascadedLED structures with interleaved tunnel junction integration.
It would appear that using tunneljunction’s in cascaded LEDs can eliminate the use of resistive p-GaN contact layers,leading to reduced voltage loss and enhanced hole injection. Moreover, by usingtunnel junction interconnects, multiple-active-region LEDs significantly enhancedlight intensity. P-GaN contact resistance appears to be a bottleneckin improving the performance of conventional nitride based LEDs.Additionally red,green and blue LED’s stacked vertically (with tunnel junctions between them)phosphor-free white light emission can be produced directly rather than using downconversion using phosphors (loosing 30% of the energy).
I'm not an expert but it appears that Tunnel Junctions using RPCVD really could be a "breakthrough" - problem now is to get it adopted and productionized; hopefully Lumiled's will fill this gap and BLG provide retrofitted tools (and/or a license to Veeco/Aixtron).
BLG Price at posting:
25.0¢ Sentiment: Hold Disclosure: Held
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