利用掃描穿隧顯微鏡探討在硒化銦上未氧化表面和氧化表面之介面接合處的電子特性

Scanning Tunneling Microscope study of InSe Surface Electronic Properties at the Fresh/Oxided Interface junction

羅子嘉(Luo Zih-Jia)

指導教授 ： 傅祖怡

國立臺灣師範大學/理學院/物理學系/碩士(2018年)

https://doi.org/10.6345/THE.NTNU.DP.001.2018.B04

摘要

硒化銦在其表面氧化後，會與塊材產生PN接面(PN junction)。當光子入射至PN接面時，會產生電子電洞對且會因為空乏區產生的內建電場而分離，促使光伏特效應(photovoltaic effect)產生的功率提升。且硒化銦備受關注的一點是其氧化表面可以透過調控氧化因素來改變光反應(photo responsivity)，且有研究表示光反應會隨著氧化程度上升，所以硒化銦很有潛力做為光探測器(photo dectector)。
硒化銦的表面形貌和電性都非常容易受到氧化影響。在氧化後硒化銦表面形貌會變得較粗糙而電性表現上會呈現更N-type的行為且能隙更大。當硒化銦氧化到達一定程度後其表面最終會生成三氧化二銦。就此形成硒化銦和三氧化二銦的異質結構(heterostructure)。根據其他巨觀的量測推測硒化銦和其表面的氧化層間會有載子轉移的現象。
為了證實上面的論述，本研究是由掃描穿隧顯微鏡探討二維層狀半導體材料硒化銦表面經過機械剝離法處理前後所形成之介面接合處(interface junction)所發生的電子特性改變的現象。並進一步從掃描穿隧能譜的曲線分析微觀尺度下呈現出介面接合處有載子轉移現象，此現象為氧化層抓走底下硒化銦塊材的電子,並且氧化層內的電洞會填補到硒化銦裡。

關鍵字

硒化銦 ； 層狀半導體 ； 氧化表層 ； 掃描穿隧顯微鏡 ； 掃描式穿隧能譜 ； 載子轉移物理現象 ； 機械剝離法

並列摘要

Indium selenide(InSe) will form a PN junction between the bulk region and oxide surface. When the photon is incident on the PN junction the electron-hole pair is generated and separated by the built-in electric field begated by the depletion region. And enhance the power which generated by photovoltaic effect. InSe center of attention is that its oxidation surface can be controlled by the oxidation factor to change the photo responsivity, the photo responsivity will increase with the degree of oxidation. Therefore indium selenide has great potential to make photodetector.
The surface topography and electrical properties of InSe surface are very susceptible to oxidation. The topography of indium selenide after oxidation will become more roughness and the performance of the electrical properties will show more N-type behavior and the bandgap more larger. When the indium selenide oxide reaches a certain degree the surface will eventually produce In2o3. Thus, form a heterogeneous structure between InSe and In2o3. According to other macroscopic measurements, it is speculated that there will be a phenomenon of charge transfer between InSe and its oxide surface.
In order to confirm the above discussion, this study was used by scanning tunneling microscopy to explore the two-dimensional layered semiconductor material InSe surface before and after mechanical exfoliation the formation of the interface junction. And further from the scanning tunneling spectroscopy curves to analysis the microscopic showing of the charge transfer phenomenon at interface junction. This phenomenon is for the oxide layer to capture the electrons where in bottom of the InSe and the holes in the oxide layer will be filled with InSe bulk.

並列關鍵字

InSe ； layered semiconductor ； oxide layer ； STM ； STS ； charge transfer physical mechanism ； mechanical exfoliation

參考文獻

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