TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Methods: The method comprises bringing first portions of thin film solar cell into liquid phase and subsequently into solid phase (16), thus forming heavily doped first type polarity region(s) extending across the entire thickness of the solar cell structure, bringing second portion of the thin film solar cell into liquid phase and subsequently into solid phase, thus forming heavily doped second type polarity regions extending across the entire thickness of the solar cell structure and that are located adjacent to the respective heavily doped first type polarity regions. The method includes forming overlayer on solar cell and locally diffusing elements from this overlayer into the tunnel recombination junction by using laser treatment, and removing the overlayer. The method comprises forming groove(s) in solar cell structure so that surface region(s) of one side wall of each groove having n type polarity and surface region(s) of the other side of groove having p type polarity; and forming electrical contact layer in each groove so that the respective surface regions of the sidewalls are in electrical contact with one another. The forming of electrical contact layer on groove includes depositing positive photo resist on the solar cell structure including the groove, directing light beam towards the solar cell structure through the transparent substrate/superstrate so that only portions of the photo resist deposited between the side walls of the respective grooves are exposed to the light beam, removing portion of photo resist exposed to the light beam, depositing conducting layer on solar cell structure so that portion(s) of respective side walls of each groove are in electrical contact with one another, and removing photo resist and conducting overlayer on photo resist.Preferred Components: The respective pairs of the adjacent re-solidified p-type and n-type regions are made of ohmic contact between the neighboring solar cells. The re-solidified n and p type regions are in intimate physical contact with one another and electrical contact between the neighboring solar cells is established by tunnel recombination p-n junction formed. The electrically conducting material is locally formed on exposed surface of re-solidified n and p type regions. The semiconductor material forming the solar cell is silicon. The overlayer film on the solar cell is titanium dioxide. The excess dopant atoms required to make p and n type regions forming part of the electrical contact between neighboring solar cells are provided by spin on dopant source or gas dopant source. The substrate/superstrate is transparent. A wavelength beam is chosen so that the light beam is absorbed in the solar cell structure. The solar cells structure is silicon based. The light beam is ultraviolet light beam.