Comparison of light emission from stain-etch and anodic-etch silicon films

Abstract

Bright visible photoluminescence (PL) has been measured in stain-etch silicon films prepared by chemical etching in a dilute hydrofluoric and nitric acid solution. The PL emission is observed to degrade exponentially when the stain-etch films are illuminated in air (intensity decreases by 1/e over 22.45 min). Anodic-etch silicon films, prepared using a novel electrochemical cell, show similar strong visible PL but a degradation rate an order of magnitude smaller. The wavelength of the PL peak for anodic-etch silicon (650–710 nm) shifts toward the blue with decreasing electrolyte HF concentration while the PL peak position of stain-etch silicon (∼650 nm) does not vary with process conditions investigated.