Coupled Nano-structures and 2D Material Hetero-structrues

Shih-Yen Lin^1*, Wei-Hsun Lin¹, Chong-Rong Wu¹, Hsuan-An Chen¹, Kuan-Chao Chen¹

¹Research Center for Applied Sciences, Academia Sinica, Taipei, Taiwan

* Presenter:Shih-Yen Lin

Compared with InAs quantum dots (QDs), less effort is put on the preparation and device applications of GaSb QDs and quantum rings (QRs) on GaAs substrates. One possible mechanism may lie on the difficult-to-control As-Sb interfaces such that inferior electrical and optical characteristics are obtained for GaSb QDs and QRs. In this report, we have demonstrated that by controlling the Sb/background As ratios, full GaSb QD or QR morphologies can be obtained on GaAs substrates. By using the coupled GaSb QR or the coupled InAs QDs with GaSb QR structures, enhanced luminescence or the transition of type-I to type-II nano-structures can be observed. Compared with traditional semiconductor materials, one of the major advantages of 2D materials is that their unique characteristics can be observed within several atomic layers, which makes them suitable for device applications with nm linewidths. Besides the search of new 2D materials, an alternate approach to enhance the device performances is through the stacking of different 2D materials. In this report, we have demonstrated that vertical WS2/MoS2 hetero-structures can be epitaxially established by sequential metal deposition/sulfurization procedures. The atomic layer etching and the equivalent selective etching of the 2D material hetero-structures are also demonstrated. On the other hand, the other group-V 2D material antimonene can also be grown on MoS2 surfaces by using the Van der epitaxy of 2D materials onto the other 2D material surface. The much lower contact resistance of the conducting/semiconductor 2D material interfaces will be advantageous for the practical application of 2D devices.

Keywords: GaSb quantum dots, GaSb quantum rings, 2D material hetero-structures