▁▁ ▁, ▁ ▁where ▁m ▁is ▁the ▁car rier ▁effective ▁mass ▁and ▁. ▁As ▁ ▁and ▁ ▁are ▁the ▁car rier ▁mob ility ▁and ▁the ▁conduct ance ▁of ▁the ▁device , ▁from ▁the ▁above ▁equation ▁and ▁the ▁Wiener - K h int ch ine ▁theorem ▁we ▁recover ▁the ▁result ▁▁ ▁, ▁ ▁obtained ▁by ▁Ny qu ist ▁from ▁the ▁second ▁principle ▁of ▁the ▁therm od ynam ics , ▁i . e . ▁by ▁means ▁of ▁a ▁macro scop ic ▁approach . ▁ ▁Generation - re com bin ation ▁( g - r ) ▁noise ▁ ▁A ▁significant ▁example ▁of ▁application ▁of ▁the ▁macro scop ic ▁point ▁of ▁view ▁expressed ▁by ▁the ▁third ▁term ▁of ▁the ▁second ▁equation ▁of ▁section ▁Fl uct u ations ▁is ▁represented ▁by ▁the ▁g - r ▁noise ▁generated ▁by ▁the ▁car rier ▁tra pping - det ra pping ▁processes ▁in ▁device ▁defect s . ▁In ▁the ▁case ▁of ▁constant ▁volt ages ▁and ▁dr ift ▁current ▁density ▁, ▁that ▁is ▁by ▁neglect ing ▁the ▁above ▁velocity ▁fl uct u ations ▁of ▁thermal ▁origin , ▁from ▁the ▁mentioned ▁equation ▁we ▁get ▁▁ ▁, ▁ ▁in ▁which ▁ ▁is ▁the ▁car rier ▁density , ▁and ▁its ▁steady ▁state ▁value ▁is ▁, ▁ ▁being ▁the ▁device ▁cross - section ▁surface ; ▁further more , ▁we ▁use ▁the ▁same ▁symbols ▁for ▁both ▁the ▁time ▁aver aged ▁and ▁the ▁instant aneous ▁quantities . ▁Let ▁us ▁first ▁evaluate ▁the ▁fl uct u ations ▁of ▁the ▁current ▁i , ▁that ▁from ▁the ▁above ▁equation ▁are ▁▁ ▁,