【公開日：2023.08.01】【最終更新日：2023.04.14】

課題データ / Project Data

課題番号 / Project Issue Number

22SH0002

利用課題名 / Title

Development of compound semiconductors based electronic devices such as FET, gas sensor, solar cell, and memristor

利用した実施機関 / Support Institute

信州大学 / Shinshu Univ.

機関外・機関内の利用 / External or Internal Use

外部利用/External Use

技術領域 / Technology Area

【横断技術領域 / Cross-Technology Area】（主 / Main）物質・材料合成プロセス/Molecule & Material Synthesis（副 / Sub）-

【重要技術領域 / Important Technology Area】（主 / Main）高度なデバイス機能の発現を可能とするマテリアル/Materials allowing high-level device functions to be performed（副 / Sub）-

キーワード / Keywords

memristor, gas sensor, heterojunction, compound semiconductor,リソグラフィ/Lithography,膜加工・エッチング/Film processing and Etching,スパッタリング/Sputtering,CVD

利用者と利用形態 / User and Support Type

利用者名（課題申請者）/ User Name (Project Applicant)

Shaibal Mukherjee

所属名 / Affiliation

Indean Institute of Technology Indore(IITI)

共同利用者氏名 / Names of Collaborators in Other Institutes Than Hub and Spoke Institutes

ARIM実施機関支援担当者 / Names of Collaborators in The Hub and Spoke Institutes

Myo Than Htay

利用形態 / Support Type

（主 / Main）共同研究/Joint Research（副 / Sub）-

利用した主な設備 / Equipment Used in This Project

SH-001：ダブル球面収差補正付透過型電子顕微鏡
SH-002：走査型透過電子顕微鏡
SH-003：原子分解能分析電子顕微鏡
SH-004：光電子分光装置
SH-006：飛行時間型二次イオン質量分析装置

報告書データ / Report

概要（目的・用途・実施内容）/ Abstract (Aim, Use Applications and Contents)

In this joint research, we focus on four different topics, which are important for the future electronic industry. The first one is to improve the quality of MgZnO/CdZnO heterostructure. In this work, we report the impact of the ZnO cap layer on mobility (μ), sheet carrier density (ns), and conductance (ns × μ) of dual ion beam sputtering (DIBS) grown MgZnO/CdZnO (MCO) heterostructure with and without Y₂O₃ spacer layer.
The second  one is concerning with  the Cu₂SnGe(S,Se)₃  (CTGSSe) light absorber thin films. This work presents the influence of substrate temperature (T_sub) and post-sulfurization on compositional, structural, electrical, and optical properties of DIBS-grown CTGSSe thin films grown on a soda-lime glass (SLG) substrate using a single target.
The third topic is focused on the 2D-MoS₂-based gas sensor. In this work, we have proposed the most viable recipe which is suitable for controlling the nucleation density of Mo and producing a 90 μm-long MoS₂ monolayer crystal and (695 × 394.8) μm² large MoS₂ monolayered film on SiO₂/Si and c-plane sapphire, respectively.
And the fourth is to implement a highly reproducible Y₂O₃ based memristor crossbar array.  Here, we report the fabrication of a stable, highly scalable, reproducible, Y₂O₃-based memristive crossbar array of (15 × 12) on silicon by utilizing a dual ion beam sputtering system.

実験 / Experimental

The following facilities of Shinshu University such as high-resolution TEM (JOEL JEM2100F), scanning TEM (Hitachi HD2300A), atomic-resolution analytical electron microscope (JOEL JEM-ARM200F NEOARM), X-ray photoelectron spectroscopy (Ulvac Phi Quantera II), and time of flight secondary ion mass spectroscopy (TOF.SIMS5-ADSD-100) were utilized for the detailed analyses of the devices, which were fabricated at the Indian Institute of Technology Indore (IITI) by DIBS and CVD techniques.

結果と考察 / Results and Discussion

Investigation of MgZnO/CdZnO heterostructure 
By analyzing the cross-sectional TEM image and selected electron diffraction patterns of the MgZnO/CdZnO heterostructures with and without Y₂O₃ spacer layer, the improvement in crystalline quality and the surface flatness is clearly confirmed in the heterojunction with Y₂O₃ spacer layer. It is also observed that by utilizing a 100-nm Y₂O₃ spacer layer, the two dimensional electron gas (2DEG) mobility of MgZnO/CdZnO heterostructure is improved by 4 times in reference to the one without any spacer. A further improvement in the 2DEG mobility is observed with the insertion of a ZnO cap layer on top of the MgZnO/CdZnO heterostructures with and without Y₂O₃ spacer layer. The detail results of this experiment are reported in the reference [1].
Study of the CTGSSe light absorber thin films
XRD results reveal that the CTGSSe thin films prepared by DIBS are preferentially (112) and (204) oriented which correspond to tetragonal crystal structure and a high-quality crystalline thin film is achieved at T_sub = 300 °C. The deposited thin films show homogeneous and distinct grain morphology with the largest grain size of 87 nm at T_sub = 300 °C as confirmed by FESEM analyses. Moreover, the post-sulfurization process has improved the thin-film crystallinity in all samples which are deposited at T_sub = RT-300 °C. Cu poor, Cu/[Ge + Sn] < 1, is achieved for the CTGSSe thin films grown at T_sub = 300 °C, as confirmed by EDX measurements. Furthermore, band gap values are measured in the range of 1.46–1.62 eV via spectroscopic ellipsometry (SE) analysis, and post-sulfurization has resulted in the bandgap widening in all the cases. Furthermore, the SE measurement helps to calculate the maximum value of the refractive index (n) and extinction coefficient (k) which are 2.20 and 1.65, respectively, at T_sub = 300 °C. The highest rectification ratio of the Al/CTGSSe/n-Si junction is 20.1 at ±1 V (for T_sub = RT) in the case of a non-sulfurized sample, while for a post-sulfurized film, it is 22.5 (at T_sub = 300 °C), as observed from the J–V analysis. The detail results of this experiment are reported in the reference [2].
Development of the 2D-MoS₂-based gas sensor
In this experiment, the MoS₂ monolayer sensing performance has been thoroughly investigated for NO₂ exposure at room temperature with a varying response of 4−57.5 for the 100−100 ppm level. The MoS₂ monolayer sensor exhibits an ultrasensitive NO₂ detection with limit of detection and limit of qualification values of 1.4 and 4.6 ppb, respectively. In addition, the first-principles-based density functional theory has been employed to analyze the adsorption of NO₂ on the surfaces of the 2D MoS₂ monolayer. It is observed that the electronic band gap of the MoS₂ monolayer after NO₂ adsorption is reduced by 0.7 eV due to molecular orbital hybridization. The detail results of this experiment are reported in the reference [3].
 Implementation of a highly reproducible Y₂O₃ based memristor crossbar array
The fabricated crossbar array (15 × 12) exhibits the intrinsic nonlinear characteristics of the memristive element by displaying a high endurance (∼7 × 10⁵ cycles), high current ratio (>200), good retention (∼1.5 × 10⁵ s), high device yield, low device-to-device (D2D) (0.25), and cycle-to-cycle (C2C) (0.608) variability in the SET/RESET voltages of the memristive device. The fabricated crossbar array structure also enables the random accessibility of the device to calibrate the readout addressing measurements by operating a (4 × 4) array of crossbar structure in a 1S-1R logic, and the same is executed without any disturbance. The detail results of this experiment are reported in the reference [4].

図・表・数式 / Figures, Tables and Equations

その他・特記事項（参考文献・謝辞等） / Remarks(References and Acknowledgements)

References
[1] Pawan Kumar, Sumit Chaudhary, Md Arif Khan, Ruchi Singh, Myo Than Htay, Rahul Prajesh, Ajay Agarwal, Shaibal Mukherjee, Impact of ZnO Cap Layer on the Performance of MgZnO/CdZnO Heterostructure with Y₂O₃ Spacer Layer, IEEE Transactions on Electron Devices, 69 (11): 5991-5995, 2022.
[2] Mayank Dubey, Gaurav Siddharth, Ruchi Singh, Chandrabhan Patel, Sanjay Kumar, Myo Than Htay, Victor V. Atuchin, and Shaibal Mukherjee, Influence of Substrate Temperature and Sulfurization on Sputtered Cu₂SnGe(S,Se)₃ Thin Films for Solar Cell Application, IEEE Transactions on Electron Devices, 69(5):2488-2493, 2022.
[3] Chandrabhan Patel, ruchi singh, Mayank Dubey, Sushil Pandey, Shrish Upadhyay, Vikash Kumar, Sharath Sriram, Myo Than Htay, Srimanta Pakhira, Victor Atuchin, Shaibal Mukherjee, Large and Uniform Single Crystals of MoS₂ Monolayers for ppb-level NO₂ Sensing, ACS Appl. Nano Mater. 5(7):9415-9426, 2022.
[4] Sanjay Kumar, Mangal Das, Myo Than Htay, Sharath Sriram, Shaibal Mukherjee, Electroforming-Free Y₂O₃ Memristive Crossbar Array with Low Variability, ACS Applied Electronic Materials, 4 (6): 3080-3087, 2022.

成果発表・成果利用 / Publication and Patents

論文・プロシーディング（DOIのあるもの） / DOI (Publication and Proceedings)

1. Pawan Kumar, Impact of ZnO Cap Layer on the Performance of MgZnO/CdZnO Heterostructure With YO Spacer Layer _{, IEEE Transactions on Electron Devices, 69, 5991-5995(2022).
   DOI: 10.1109/TED.2022.3206172}
   
2. Mayank Dubey, Influence of Substrate Temperature and Sulfurization on Sputtered Cu₂SnGe(S,Se)₃ Thin Films for Solar Cell Application, IEEE Transactions on Electron Devices, 69, 2488-2493(2022).
   DOI: 10.1109/TED.2022.3159509
   
3. Chandrabhan Patel, Large and Uniform Single Crystals of MoS₂ Monolayers for ppb-Level NO₂ Sensing, ACS Applied Nano Materials, 5, 9415-9426(2022).
   DOI: 10.1021/acsanm.2c01701
   
4. Sanjay Kumar, Electroforming-Free Y₂O₃Memristive Crossbar Array with Low Variability, ACS Applied Electronic Materials, 4, 3080-3087(2022).
   DOI: 10.1021/acsaelm.2c00472
   

口頭発表、ポスター発表および、その他の論文 / Oral Presentations etc.

1. 1: Sumit Chaudhary, Pawan Kumar, Kumari Jyoti, Myo Than Htay, Shaibal Mukherjee, Analysis of Cut-off and Maximum Oscillation Frequency of Oxide HEMT with MgO Spacer Layer, Organic and Inorganic Electronics Symposium: O&I Symposium, O5, 2022(Jun. 11).
2. 2: Chandrabhan Patel, Ranjan Kumar, Myo Than Htay, Shaibal Mukherjee, Role of alkaline halides on MoS2 monolayer growth via CVD, Organic and Inorganic Electronics Symposium: O&I Symposium, O6, 2022(Jun. 11).

特許 / Patents

特許出願件数 / Number of Patent Applications：0件
特許登録件数 / Number of Registered Patents：0件