<p>A shingle circuit array and a method of assembling the shingle circuit is provided. The array has a shingle circuit with a substrate (11), an insulation film layer, a metal layer and TPV cells (17) connected to the metal layer in series forming a shingle pattern with terraces. The substrate (11) is of CTE matched material. The metal layer may be copper pads deposited on the terraces. The TPV cells (17) are bonded to the copper pads and may be GaSb cells. Substrate (11) materials include AlSiC or a Cu/Invar/Cu laminate sheet. The AlSiC material may be a microstructure having a continuous Al-metal phase with a discrete SiC particulate phase. The substrate (11) may also be an enameled cast-iron substrate. The shingle circuit array may be provided in a TPV generator.</p>