The open circuit voltage depends on the fabrication process in many cases. For instance, a pn unbiased diode presents a so-called build-in voltage, which is depending on the doping concentrations in each regions, essentially it depends on the doping process. 

Also, the MOS technology for Integrated circuits are strongly depends on the cleaning room conditions. A contamined oxide by Na+, K+ shift the threshold voltage.

The open circuit voltage depends on the fabrication process mostly through its dependence on the lifetime of minority carriers on both sides of the the junction of the solar cells. Also it is affected by mobility of the material. Both minority carriers lifetime and mobility decrease with the increase of fabrication defects. The doping concentrations as a process parameter affects the the open circuit voltage in the sense that the open circuit voltage increases by increasing the the doping to some optimum doping. The thickness of the material which can be varied by the fabrication process affects the open circuit voltage. It must be made sufficiently large to absorb all the penetrating incident radiation.

A very detailed analysis of the effect of the physical and technological parameters on the solar cell performance parameters including the open circuit voltage is given in the link: https://www.researchgate.net/profile/Abdelhalim_Zekry/publications?pubType=book&ev=prf_pubs_book

Hi Mostefa,

the answer really depends on what you are talking about. Sources like solar cells, fuel cells, batteries or voltage converters or electronic devices like diodes, transistors, integrated circuits or even passives? Please give us more information.

Best, Steffen

Hi Steffen

Thank you