A MINIATURIZED HIGH-VOLTAGE SOLAR-CELL ARRAY AS AN ELECTROSTATIC MEMSPOWER-SUPPLY

A hydrogenated amorphous silicon (a-Si:H) solar cell array that is des igned as an on-board power source for electrostatic microelectromechan ical systems (MEMS) is presented, A single cell consists of a triple l ayer of p-i-n/p-i-n/p-i-n a-Si:H and produces an open circuit voltage (V-oc) of 1.8 similar to 2.3 V, a short circuit current density (J(sc) ) of 2.8 mA/cm(2), and fill factor (FF) of 0.495, A series interconnec ted array of 100 single solar cells (total array area of 1 cm(2)) is f abricated in an integrated fashion and produces an array V-oc of 150 V , and array short circuit current (I-sc) of 2.8 mu A under Air Mass (A M) 1.5 illumination, To demonstrate the usefulness of this solar cell array as an on-board power source for electrostatically driven microma chined devices, it has been packaged with a movable micromachined sili con (Si) mirror in a hybrid manner. The movable Si mirror is directly driven by the cell array electrical output, and the motion of the mirr or plate has been observed reproducibly. Variation of light intensity and/or number of illuminated cells produces different values of array V-oc, thus enabling control of the deflection of the Si mirror by vari ation of incident light intensity.