Overcoming the Problem of Electrical Contact to Solar Cells Fabricated using Selective‐Area Silicon Nanopillars by Cesium Chloride Self‐Assembly Lithography as Antireflective Layer

Abstract

Selective‐area nanopillar‐textured solar cells were fabricated by using a convenient method to overcome the problem of metal contacts on the nanopillars surfaces. A Ti/Ag electrode layer was deposited onto the planar surface after phosphorous doping, and then the nanopillars were fabricated on the surface by using cesium chloride (CsCl) self‐assembly lithography. With this method, nanopillars of approximately 150 nm average diameter and heights from 120 to 480 nm [corresponding inductively coupled plasma (ICP) etching time from 15 to 75 s] were fabricated on silicon surface as an antireflection layer. Compared with the solar cell with nanopillar arrays covering the entire front surface, the selective‐area nanopillars device exhibited better electrode contacts, and consequently better performance: the photovoltaic conversion efficiency (PCE) improved from 12.38 to 15.58 %. The heights of the nanopillars also had a significant effect on the PCE of the solar cells, for which the nanopillars of 240 nm height produced the solar cell with the best performance.

Optimal design of an antireflection coating structure for enhancing the energy-conversion efficiency of a silicon nanostructure solar cell

“…13,[24][25][26] In addition, silicon nanocone and nanopillar arrays in the silicon wafers have been generated by using ICP etching and extreme ultraviolet lithography. 10,[27][28][29] As one widely-used method for semiconductor processing, the ICP etching method has been applied, with several advantages, including low damage, high etching rates, high anisotropy, and high selection ratio. 30 The ICP method is a very complex physical and chemistry process, which is composed of two components: one is the interaction between the free radicals, metastable particles, and atoms by the inductively coupled grow discharge of etching gas; the other is the interaction between the active particles and the surface of a sample.…”