Fig. 4: Experimental validation for the effects of intensity and gradient.
From: Anomalous photoelectrochemical etching of undoped semiconductor surfaces
a The structured light field consisting of sixteen square areas numbered from 1 to 16, each with the same light intensity of the small square in the center and a different light intensity of the peripheral region. b The etching results of a-PEC etching using the light field a with a total intensity of 6 μW, where h means the average height of the central square relative to the unilluminated region. c The relationship between height h and gradient g (defined as g = (I1 − I2)/I1, in which I1 and I2 are the optical power density of the central square and peripheral region, respectively). d The structured light field consisting of four partitions, each with the same light intensity as the central small circular area and a different light intensity in the peripheral region. e The etching results using the light field d with a total intensity of 4 μW. f The relationship between height h and light intensity I (the optical power intensity of the central circular area). g The structured light field consisting of four rectangular arrays of different sizes. h, i, j, k Are the etching results of 8 × 8, 4 × 4, 2 × 2, and 1 × 1 rectangles, respectively, by using the light field g. Source data are provided as a Source data file.
