deletions | additions       diff --git a/subsection_Hydride_Vapor_Phase_Epitaxy__.tex b/subsection_Hydride_Vapor_Phase_Epitaxy__.tex  index 5032fd0..c3e9591 100644  --- a/subsection_Hydride_Vapor_Phase_Epitaxy__.tex  +++ b/subsection_Hydride_Vapor_Phase_Epitaxy__.tex 
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HPVE involves the reaction of gallium metal with HCl gas at 750 C, which forms GaCl. A nitrogen gas flow then transports the GaCl to a chamber wherein it reacts with ammonia gas directly upon a sapphire substrate to form nanowires. Shin's team used this process to form straight nanowires that were grown perpendicular to the substrate, with the diameters ranging from 80 to 120 nm. The size of the nanowires was able to be modified by controlling the temperature. One of the more unique aspects of HVPE synthesis was that fact that growth temperature chamber was kept around 480 C, compared to temperatures ranging from 850 – 1050 C for VLS. \cite{Kim_2002} More recently, a team in 2012 managed to optimize the process to create various morphologies of GaN nanostructures. This was attained by varying the ratio of HCl and ammonia gas, as well as the temperature in the reaction chamber. The group also utilized a silicon substrate, with is more inexpensive than a sapphire one. \cite{Shin_2012}  More recent advances in HPVE synthesis have been developed by the Avit group, who managed to create a growth method that couples high lengths of nanowires with extremely high growth rates. The Grown on a sapphire substrate, the  nanowires grown have defect-free crystal structures that are similar to previously grown nanowires that utilize VLS. Another benefit of their process was the usage of a HPVE furnace at atmospheric pressure, which would reduce the cost of HPVE furnaces for scale-up. Therefore, by using HPVE, researchers were able to develop GaN nanowires efficiently while avoiding impurities that may have been present in VLS and other synthetic methods. \cite{Avit_2014}