The morphology control of aligned silicon nanowires (SiNWs) is highly desirable as SiNWs demonstrated high prospect in a variety of applications. Besides the control over length, shape and distribution of aligned SiNWs, the fine-tuning of tilting angles thereof also attracted intense interest. Up to now, only several discrete tilting angles have been reported. In this Letter, the ability to fine-tune the tilting angle of SiNWs is demonstrated and the range that can be achieved is identified. Our technique employs the anisotropic characteristic of the etching process using custom-produced off-cut Si wafers of various orientations as substrates. With this technique, a uniquely favoured etching direction can result and the tilting angle can be precisely controlled. Tilted SiNWs with tilting angles from 0° to 50° relative to the wafer normal were obtained. The mechanism of the tilting angle manipulation is also discussed.
- Chemical etching