Title :
The dependence of reactively sputtered ZnO electronic properties on growth parameters for use as buffer layers in CuInxGa1-x Se2 solar cells
Author :
Bhatt, R. ; Sankaranarayanan, H. ; Ferekides, C.S. ; Morel, D.L.
Author_Institution :
Dept. of Electr. Eng., Univ. of South Florida, Tampa, FL, USA
fDate :
29 Sep-3 Oct 1997
Abstract :
High electronic quality undoped ZnO deposited by reactive sputtering has been developed for use as the buffer layer in CuInx Ga1-xSe2 solar cells. Growth mechanisms are shown to differ from those resulting from conventional sputtering with ZnO targets. Film resistivity can be varied from 10-2 ρ-cm to unmeasurable by variation of the growth parameters. Mobilities of films grown at substrate temperatures of 200°C are in the range 25-30 cm2/V-s. Annealing at 325°C increases mobilities to the 35-40 cm2/V-s range. The resulting resistivity, however, is dominated by the resulting carrier concentration which is controlled by oxygen vacancies. Devices fabricated with reactively sputtered buffer layers have matched the performance of the best literature results
Keywords :
annealing; carrier density; carrier mobility; copper compounds; electrical conductivity; gallium compounds; indium compounds; semiconductor growth; solar cells; sputtered coatings; vacancies (crystal); zinc compounds; 200 C; 325 C; CuInxGa1-xSe2 solar cells; CuInGaSe2; ZnO; annealing; buffer layers; carrier concentration; film mobilities; film resistivity; growth mechanisms; growth parameters; oxygen vacancies; reactive sputtering; reactively sputtered ZnO electronic properties; substrate temperatures; undoped ZnO deposition; Annealing; Buffer layers; Conductive films; Conductivity; Phase change materials; Photovoltaic cells; Sputtering; Substrates; Temperature distribution; Zinc oxide;
Conference_Titel :
Photovoltaic Specialists Conference, 1997., Conference Record of the Twenty-Sixth IEEE
Conference_Location :
Anaheim, CA
Print_ISBN :
0-7803-3767-0
DOI :
10.1109/PVSC.1997.654108
