Development of Luxmeter Based on Ba0,25Sr0,75TiO3 Ferroelectric Material

Ba0,25Sr0,75TiO3 (BST) thin films has been deposited on a Si (100) p‐type substrate by chemical solution deposition (CSD) method followed by spin coating technique (at 3000 rpm rotational speed for 30 seconds) and annealing process at the temperature around 850° C for 15 hours. The films show a maximum optical absorption at green light. An I–V investigation on the films results in agreement that the thin films have a photodiode characteristic. Electrical conductivity of the BST thin films is in the range of 2.79×10−7 to 5.3×10−7 S/cm, it is the range of semiconductor materials. The electrical conductivity and photocurrent increase when the light intensity increases from 1000 to 6000 Lux. A BST thin film has been utilized as a light meter in an ATMega8535 microcontroller since it is sensitive with a light intensity change. Base on calibration and validation curves, a measurement using this microcontroller results in comparable light intensity values with that result from a standard instrument.