Response of c-Si PV arrays under monochromatic light for MEMS power supply

There is an increasing number of portable or ubiquitous applications where compact and reliable energy supply systems are required in the low end of the power range, but where the output voltage has to be compatible with conventional electronic equipment. In this work, the option of small-sized photovoltaic arrays designed to convert monochromatic light is explored along with improvements in the fabrication process of c-Si 'flip-chip' assembly and c-Si monolithic arrays. Arrays having nine cells connected in series (0.8–1.4 cm2 each) have been fabricated. Photovoltaic response under several monochromatic light wavelengths has been measured and compared to reference solar AM1.5 light. Electrical results under standard solar spectrum AM1.5 and 1 SUN irradiance show open circuit voltages, Voc, short circuit current densities, Jsc, and maximum delivered powers, Pm, of: 5 V and 4.1 V, 21.7 mA cm−2 and 24.5 mA cm−2, and 4.5 mW and 3.8 mW for the 'flip-chip' and monolithic technologies respectively. Typically, open circuit values in the range of 4.5 V, short circuit current densities in the vicinity of 45 mA cm−2 and maximum power in the range of 2 mW can be obtained for monochromatic illumination of 830 nm wavelength with 20 mW of incident power.