Study of heterostructures of Cu3BiS3–buffer layer measured by Kelvin probe force microscopy measurements (KPFM)

2014 ◽  
Vol 92 (7/8) ◽  
pp. 892-895 ◽  
Author(s):  
F. Mesa ◽  
D. Fajardo
Keyword(s):  
Thin Films ◽  
Solar Cells ◽  
Buffer Layer ◽  
Doping Concentration ◽  
Kelvin Probe Force Microscopy ◽  
Buffer Layers ◽  
Limiting Factor ◽  
Kelvin Probe ◽  
Force Microscopy ◽  
Electronic Activity

The interface formed between Cu3BiS3 thin films and the buffer layer is a potentially limiting factor to the performance of solar cells based on Al/Cu3BiS3/buffer heterojunctions. The buffer layers of ZnS and In2S3 were grown by co-evaporation, and tested as an alternative to the traditional CdS deposited by chemical bath deposition. From the Kelvin probe force microscopy measurements, we found the values of the work function of ZnS, In2S3, and CdS, layers deposited into Cu3BiS3. Additionally, different electronic activity was found for different grain boundaries (GBs), from studies under illumination, we also found the net doping concentration and the density of charged GB states for Cu3BiS3 and Cu3BiS3/CdS.

scholarly journals Junction formation of Cu3BiS3 investigated by Kelvin probe force microscopy and surface photovoltage measurements

2012 ◽  
Vol 3 ◽  
pp. 277-284 ◽  
Author(s):  
Fredy Mesa ◽  
William Chamorro ◽  
William Vallejo ◽  
Robert Baier ◽  
Thomas Dittrich ◽  
...  
Keyword(s):  
Band Gap ◽  
Buffer Layer ◽  
Kelvin Probe Force Microscopy ◽  
Buffer Layers ◽  
Surface Photovoltage ◽  
Excitation Wavelength ◽  
Kelvin Probe ◽  
Band Bending ◽  
Force Microscopy ◽  
Junction Formation

Recently, the compound semiconductor Cu3BiS3 has been demonstrated to have a band gap of ~1.4 eV, well suited for photovoltaic energy harvesting. The preparation of polycrystalline thin films was successfully realized and now the junction formation to the n-type window needs to be developed. We present an investigation of the Cu3BiS3 absorber layer and the junction formation with CdS, ZnS and In2S3 buffer layers. Kelvin probe force microscopy shows the granular structure of the buffer layers with small grains of 20–100 nm, and a considerably smaller work-function distribution for In2S3 compared to that of CdS and ZnS. For In2S3 and CdS buffer layers the KPFM experiments indicate negatively charged Cu3BiS3 grain boundaries resulting from the deposition of the buffer layer. Macroscopic measurements of the surface photovoltage at variable excitation wavelength indicate the influence of defect states below the band gap on charge separation and a surface-defect passivation by the In2S3 buffer layer. Our findings indicate that Cu3BiS3 may become an interesting absorber material for thin-film solar cells; however, for photovoltaic application the band bending at the charge-selective contact has to be increased.

Thin films of amphiphilic polyelectrolytes. Soft materials characterized by Kelvin probe force microscopy

Polymer ◽  
2013 ◽  
Vol 54 (21) ◽  
pp. 5733-5740 ◽  
Author(s):  
X.G. Briones ◽  
M.D. Urzúa ◽  
H.E. Ríos ◽  
F.J. Espinoza-Beltrán ◽  
R. Dabirian ◽  
...  
Keyword(s):  
Thin Films ◽  
Soft Materials ◽  
Kelvin Probe Force Microscopy ◽  
Kelvin Probe ◽  
Force Microscopy
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