Grid Ditching for Multi-wavelength Visible-light Emission in Three Dimensions Using Porous Silicon

Abstract

A new approach of three-dimensional electro-chemical etchings both in vertical and lateral current directions on grid ditched Si pn-structures is originally proposed. Under the stimulation of UV light, lateral etchings on the several ditching zones result in distinct porosities on porous Si, which generate visible lights at various wavelengths. Therefore, this novel method enables the simultaneous emission of several wavelengths of adjustable visible light from a single Si-based device. Moreover, the etching conditions on porous Si films and their related wavelengths can be fine-tuned by area sizes. Compared with the conventional method, the new approach provides a new option for multi-wavelength chip design with a precise patterning for porous Si without any mask and photoresist. In conclusion, a novel method based on three-dimensional electrochemistry etching on a grid ded pn-diode structure is initially described to create a multi-wavelength light emission on a single porous Si chip. This method works well for mask-free patterning, wavelength adjustment by area size, and multi-wavelength light emission chips. A precise light emission pattern corresponding with the ditching contour is produced by the patterning design using/without hole-pumping, porous Si structures with various porosities on different zones.