▁and ▁ar sen ic ▁v ap ors ▁react , ▁and ▁free ▁mole cules ▁depos it ▁on ▁a ▁seed ▁cry stal ▁at ▁the ▁cool er ▁end ▁of ▁the ▁furn ace . ▁Li qu id ▁enc aps ulated ▁C zo ch ral ski ▁( LE C ) ▁growth ▁is ▁used ▁for ▁producing ▁high - p urity ▁single ▁cry st als ▁that ▁can ▁exhib it ▁semi - ins ulating ▁characteristics ▁( see ▁below ). ▁ ▁Altern ative ▁methods ▁for ▁producing ▁films ▁of ▁Ga As ▁include : ▁V PE ▁reaction ▁of ▁g ase ous ▁gal li um ▁metal ▁and ▁ar sen ic ▁tr ich lor ide : ▁ 2 ▁Ga ▁+ ▁ 2 ▁ ▁→ ▁ 2 ▁Ga As ▁+ ▁ 3 ▁ ▁MO C VD ▁reaction ▁of ▁trim eth yl gal li um ▁and ▁ar s ine : ▁ ▁+ ▁ ▁→ ▁Ga As ▁+ ▁ 3 ▁ ▁M ole cular ▁beam ▁ep it axy ▁( MB E ) ▁of ▁gal li um ▁and ▁ar sen ic : ▁ 4 ▁Ga ▁+ ▁ ▁→ ▁ 4 ▁Ga As ▁or ▁ 2 ▁Ga ▁+ ▁ ▁→ ▁ 2 ▁Ga As ▁ ▁Ox id ation ▁of ▁Ga As ▁occurs ▁in ▁air , ▁de grad ing ▁performance ▁of ▁the ▁sem icon duct or . ▁The ▁surface ▁can ▁be ▁pass iv ated ▁by ▁depos iting ▁a ▁cub ic ▁gal li um ( II ) ▁sul f ide ▁layer ▁using ▁a ▁t ert - but yl ▁gal li um ▁sul f ide ▁comp ound ▁such ▁as ▁(. ▁ ▁Sem i -