Ultrathin Piezotronic Transistors with 2-Nanometer Channel Lengths

Transcription

1 Ultrathin Piezotronic Transistors with 2-Nanometer Channel Lengths Longfei Shuhai Guoyun Gao,, Yaokun Pang,, Xin Yin, & Xiaolong Feng, # Laipan Zhu,, Yu Bai,, Libo Chen,, Tianxiao Xiao,, Xudong Wang, & Yong Qin,*,, and Zhong Lin These authors contributed equally to this work. * zhong.wang@mse.gatech.edu * qinyong@xidian.edu.cn This word file includes: Figure S1 to S13 Table S1 References

2 Supplementary Figures Figure S1. Molecular structure of ZnO ultrathin film described the c-axis orientation. Figure S2. Scanning electron microscope image of ZnO ultrathin films. Scale bars, 50 µm.

3 Figure S3. Low-magnified TEM image of ZnO ultrathin film. Scale bar, 3 µm. Corresponding SAED pattern of the ZnO ultrathin film shown in b reveals a single-crystalline hexagonal lattice with a d-spacing of nm.

4 Figure S4. XPS of ZnO ultrathin films. XPS spectrum of Zn, S and Na, respectively.

5 Figure S5. Probing the out-of-plane piezoelectricity of ZnO ultrathin film. a, Ultrathin ZnO film consists of Zn O Zn stacking with the Zn atom centered in the tetrahedron (bottom left). Viewing ZnO crystal structure from the side (bottom right). b, With an external electric field pointing along the c-axis, the dipole is stretched and the unit cell is elongated, creating tensile strain in the z direction and compressive strain in the x direction. c, Schematic illustration of local characterization of out-of-plane piezoelectricity. The high-precision deformation actuator can be implemented using accurate positioning of the materials surface by vertical inverse piezoelectricity.

6 Figure S6. Topography and phase images of PFM characterization of ZnO ultrathin film with different tip voltages (1.5 to 6.5 V) applied. The topography images show that the ZnO ultrathin films are not damaged when applying the external potential of V on its surface. The phase images represent obvious phase difference between the ZnO ultrathin film and the substrate.

7 Figure S7. Statistical amplitude difference between the ZnO ultrathin film and the substrate. Figure S8. Band diagrams of metal-semiconductor interfaces of metal-zno bulk material contact and metal-zno ultrathin layer contact.

8 Figure S9. a-b) Current I presented in semilog form vs V. c-d) Current I presented in semilog form vs V 1/4.

9 Figure S10. Calculated Schottky barrier height change as a function of the applied pressure. Figure S11. a, The asymmetric modulation of carrier transport by stress under opposite drain bias in ultrathin piezotronic transistor shows characteristics of piezotronic effect. b, ln(di/dv)-v curve from the non-linear fitting curves of I-V characterization.

10 Figure S12. Real-time measurement of the current through ultrathin piezotronic transistor that reversibly switches between the closed and open forms upon pressure pulses at 1.0 V bias. The response is highly repeatable in more than 40 on/off cycles and no obvious degradation is observed. The average current of on state is about 13 na. Figure S13. The optical image of ultrathin piezotronic transistors.

11 Table S1. Summary of piezoelectric coefficients from different materials. Materials Morphology Piezo. Coefficient d 33 (pm/v) Reference ZnO ultralthin film ~23.7 This Work ZnO Nanoplatelet 18.9~22.5 (1) ZnO Bulk ~12.4 (2) ZnO Pillar ~7.5 (3) ZnO Nanorod 4.41±1.73 (4) ZnO Nanobelt 14.3~26.7 (5) GaN Nanowire ~12.8 (6) NaNbO 3 Nanowire 0.85~4.26 (7) KNbO 3 Nanowire ~7.9 (8) BaTiO 3 Nanowire ~16.5 (9) α-in 2 Se 3 Thin film ~45 (10) TMCM-MnCl3 film ~185 (11)

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