Fig. 1: Schematic of the anomalous effect in PEC etching and the in-house developed optical fabrication system.
From: Anomalous photoelectrochemical etching of undoped semiconductor surfaces
a The schematic diagram illustrating the difference between the anomalous phenomenon and the conventional PEC etching. b The experimental system consisting of PEC etching and in-situ monitoring modules (L lens, M mirror, P polarizer, BS beam splitter, SLM spatial light modulator, OBJ objective). c The SEM images of an etched pattern (i.e., the “USAF 1951” resolution test target pattern) on n-type and undoped GaAs wafers based on a physical photomask. d The structured light field of an array of 36 circles captured by the camera. e The fabricated microlens array obtained by the conventional PEC etching on an n-doped GaAs wafer. f The fabricated microlens array obtained by the a-PEC etching on an undoped GaAs wafer.
