news review
rhombus4
What are the benefits
Quantum dot
of sold state lighting?
technology
'experiences
Solid state lighting offers a number of they tend be twice as bright.
benefits over fluorescent or Further benefits of LEDs include
incandescent lamps. being safer – as they run on low
demand'
Solid state lighting differs from voltage and tend not to heat up –
fluorescent or incandescent lamps being flexible thanks to their size Quantum dot - or fluorescent nano-
– which use filaments and gases and being more durable, as they crystalline particle - maker Nanoco has
in a glass bulb to create light – as are able to withstand vibrations. reported that demand for the
it converts electricity to light The Lighting Research Centre semiconductor technology is increasing,
through semiconductors. (LRC) noted: "LED lighting especially for use in solar cells and light-
Although light-emitting diodes systems have already proved to emitting diode (LED) backlighting.The
(LEDs) were first developed over be very effective in indicator particles can be used in cleantech
40 years ago, so far they have applications where brightness, applications such as next-generation
primarily been used in devices visibility and long-life are photovoltaic cells and low-energy lighting,
such as torches and laser important, such as in exit signs as well as for flatscreen televisions and
pointers. and traffic signals." biological marking.
However, research and development could According to the group, there are numerous LED lighting which includes quantum dots
well mean they are increasingly used in solid possibilities where the items can be used in is 60 times more efficient than
state lighting. Organic light-emitting diodes the future, such as lighting, under-shelf incandescent light bulbs and twice as
or polymer light-emitting diodes can also be features, outdoor parking and step marking. efficient as mercury-discharge lighting, the
used in the devices as well. Solid state It may be possible in the future for them to company stated. As such, Nanoco has
lighting is often used in traffic lights and be used to cover entire walls and ceilings, reported it is moving towards the mass
remote controls. The technology looks like it as the technology becomes more advanced, production of quantum dots that do not
may revolutionise the lighting industry and the organisation concluded. contain heavy metals, because in order to
there are many advantages of using expand the semiconductor market, there
compound semiconductors in such items. Recently, the LRC conducted research into needs to be a move away from technology
understanding which factors affect the based on cadmium.
LEDs can reduce operating costs as they performance of standalone solar-powered
have a longer life to incandescent light LED lighting systems. It found that generally
bulbs. While the latter option lasts an high irradiance, low temperature and
average of 1,000 hours, the former can maximum power point tracking controller
provide 50,000 hours or more of life – and can provide the fastest charging rates.
LED semiconductors see uptake for
solid-state lighting'
The semiconductor market is expected to (MOCVD) equipment - a technique for
further grow, with the light emitting diode depositing thin layers of atoms on to a "The market has really started to move for
(LED) industry enjoying greater financial semiconductor wafer. us. We're working hard to meet the
security, it has been reported. demand that seems to be mushrooming in
"LED-based backlighting has reached a front of us," chief executive Michael
Over the past two months, three companies tipping point where we expect to see Edelman told Reuters.
have raised almost $800 million (£481 significant acceleration of the market for
million) for LED development and the Has LED-backlit liquid crystal display TVs from Nanoco is the only manufacturer which can
LED Lighting Reached a Tipping Point? 2010 on," said Steve Entwistle, vice- currently supply production quantities of
report from Strategy Analytics said this president of Strategy Analytics' strategic such nanoparticles which do not use a
indicates accelerated adoption of the technologies practice. regulated heavy metal. It recently announced
semiconductor backlighting technology. it has signed a joint development agreement
Using MOCVD enables a range of with a major Japanese electronics company
Furthermore, the financial support highlights semiconductor photodetectors and lasers to be to develop fluorescent nano-crystalline
a move towards solid-state lighting, with the built as a number of layers can be built up each particles for use in liquid-crystal display
company also noting backlogs for to a precisely controlled thickness to enable televisions and LEDs.
metalorganic chemical vapour deposition specific electrical and optical properties.?
10 www.compoundsemiconductor.net November / December 2009
Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44