Title :
High voltage Cu(In,Ga)Se2 devices with Ga-profiling fabricated using co-evaporation
Author :
Bodegård, Marika ; Lundberg, Olle ; Malmström, Jonas ; Stolt, Lars ; Rockett, Angus
Author_Institution :
Angstrom Solar Center, Uppsala Univ., Sweden
Abstract :
The influence of bandgap profiling of Cu(In,Ga)Se2 absorbers for thin film solar cells has been investigated. Profiles have been obtained by depositing CuGaSe2 back surface layers in the beginning of the Cu(ln,Ga)Se2 growth process. Two different concentrations of Ga was used for the nongraded part of the Cu(ln,Ga)Se2 film corresponding to Ga/(Ga+In) ratios of 0.2 and 0.5. The interdiffusion of Ga and In was studied and it was found that, although substantial interdiffusion occurred, a back surface layer with a high Ga content remained as analyzed with SIMS and XRD. The main influence on the solar cell parameters, by widening of the bandgap towards the back contact using this Ga-rich back surface layer, was found to be an enhancement of the efficiency by improved voltage
Keywords :
X-ray diffraction; chemical interdiffusion; copper compounds; energy gap; gallium compounds; indium compounds; secondary ion mass spectroscopy; semiconductor device measurement; semiconductor device testing; semiconductor thin films; solar cells; Cu(In Ga)Se2; Cu(In,Ga)Se2 thin film solar cell absorbers; CuGaSe2; CuGaSe2 back surface layers; Ga-rich back surface layer; SIMS; XRD; bandgap profiling effect; bandgap widening; efficiency enhancement; interdiffusion; solar cell parameters; voltage improvement; Large-scale systems; Matrices; Optical reflection; Photonic band gap; Production; Sputtering; Substrates; Temperature; Voltage; X-ray scattering;
Conference_Titel :
Photovoltaic Specialists Conference, 2000. Conference Record of the Twenty-Eighth IEEE
Conference_Location :
Anchorage, AK
Print_ISBN :
0-7803-5772-8
DOI :
10.1109/PVSC.2000.915867
