Electrical and Photoluminescence Study of Undoped CuGaSe2 Single Crystal Thin Film
Photoluminescence (PL) characteristics have been studied on undoped CuGaSe2 single crystal thin films grown on GaAs (001) substrate by migration-enhanced epitaxy. Room temperature PL spectrum of an undoped layer clearly shows free excitonic emission bands related to the minimum band edge and to the split-off valence band, but no discernible emission has been observed in the low-energy area. At 4.2 K, the excitonic emission due to the split-off valence band disappears. Instead, two additional emissions appear at 1.715 and 1.68 eV which are attributed to the bound exciton and band-to-acceptor transition.
KeywordsBeam Equivalent Pressure Undoped Layer Free Exciton Emission Sommerfeld Effect Beam Equivalent Pressure Ratio
This work is partly supported by Grants-in-Aid for Scientific Research B (23360163) and Young Scientists B (20760203 and 22760233) from the Japan Society for the Promotion of Science (JSPS) and by the Global COE Program “Practical Chemical Wisdom” from the Ministry of Education, Culture, Sports, Science and Technology (MEXT).