Study Of Preparation And Properties Of Black Silicon

The surface textured silicon, namely black silicon, is widely recognized for its highabsorption of visible light in the field of semiconductor. Black silicon can be used insolar cells, detectors, optic-diode, field emitter, luminescence and other optoelectronicdevices, and the application of black silicon has a quite impressive prospect. Meanwhile,the methods of black silicon fabrication have different advantages, chemical method issimple, cheap, and suitable for mass production, which provides the possibility for thecommercial application of the black silicon. This subject fabricated black silicon withacid etching, alkaline corrosion and electrochemical corrosion methods, and did acomparative study of their surface characteristics, optical properties, optoelectronicproperties. We also prepared ohmic electrode on black silicon sample, fabricated blacksilicon based optoelectronic devices with high responsivity in two structures: MSM andN+/N.The study of black silicon under different conditions includes the surface microstructure characteristics, optical characteristics, the photoelectric conversioncharacteristics, the main research work and their results are as follows:1、 Preparing acid etching solution with HF, H₂O₂, HAuCl₄, C₂H₅OH and H₂O,etching crystalline silicon with acid etching solution for7minters under differenttemperature, which showed that the higher the corrosion temperature, the greater thenanopore on black silicon surface.2、 Preparing Si3N4mask （2μm:2μm） on crystalline silicon with photolithography,then etching masked crystalline silicon with KOH and isopropyl alcohol under85.7℃,which showed black silicon with neatly arranged micro-structure.3、 Combining acid etching and alkaline etching method for the preparation ofblack silicon, which showed the offset of each other.4、 Etching crystalline silicon in the ethanol of HF with current, which showedthat the longer corrosion the larger and deeper of the hole, too long corrosion caused theformation of gully hole.5、 The results of integrating sphere test showed that acid etched black silicon only improved the visible light absorption（94%）; alkali corroded black silicon andelectrochemical etched black silicon have increased absorption both in visible andinfrared light, the absorption rate of visible light are both85%, for the absorption rate ofinfrared light, the former is30%, the latter is15%; Black silicon doped with Te hasimproved the absorption rate of infrared light by20%, but reduced the absorption rate ofvisible light.6、 Fabricating metal electrodes with vacuum deposition and magnetronsputtering method, the results showed that the annealing of300℃is essential for ohmiccontract.7、 The I-V characteristics test of black silicon based devices showed that theMSM structure device exhibits photosensitive resistance characteristic and the N+/Nstructured device turns out to be a photosensitive diode, both of which can be applied tophotodetectors, photodiodes, solar cells and other optoelectronic; compared withconventional silicon devices, black silicon based devices improved the sensitivity andresponse rate.