III-nitride nanowires for solar light harvesting: A review

The world needs economical and sustainable alternate energy sources to combat the irreversible phenomenon like global warming. Solar photovoltaic technology, which converts sunlight directly to electricity, is the most potential candidate for alternate energy source. On the other hand, increasing global pollution due to energy emission compels the worldwide researcher community to deliberate over various green fuels. Recently due to numerous advancements hydrogen fuel cells are thought to be the green power source of 21st century and may develop the hydrogen economy. However, despite of many promising breakthroughs energy production harvesting solar light does not find wide spread applications due to their low efficiency associated with unsuccessful utilization of entire solar spectrum which leads researchers to consider materials with multi energy band gap. Due to their unique property of band gap tuning (~6.2 eV for AlN to ~0.65 eV for InN) III-nitride nanowire structures have been extensively investigated in the past decade in pursuit of multi band gap materials. Intensive research efforts have been paid into studying GaN, InN, InGaN, AlN and their different compositions. It is clear that this material family has enormous potential in harvesting solar energy to light the new dawn of clean and sustainable energy sources. In this article, we present an overview on recent advancements in III-nitride solar energy devices. We have made a review for more than 200 articles in this regard. All the recent developments in realizing III-nitride nanostructures and novel yet recent advances in III-nitride solar devices are reviewed in Section 2 and its subsequent subsections. The III-nitride nanowire photovoltaic devices are discussed in Section 3 whereas Section 4 deals with the current progresses in artificial photosynthesis involving III-nitride nanowires. Finally in Section 5 the present challenges in realizing high efficiency III-nitride nanowire solar energy devices are summarized along with paths for future work.