---
# System prepended metadata

title: Mg insertion into Sb layers
tags: [' Magnesium', ' XPS', Sb, ' Mg', ' Antimony']

---

---
tags: Sb, XPS, Mg, Antimony, Magnesium
---

Mg insertion into Sb layers
===========================

## Sb depostion in literature




![](https://i.imgur.com/BLUt6Jk.png)

### XPS

The 3d XP spectra of Sb is undergoing plasmon loss features that were already described in literature [pollak1974]:
![](https://i.imgur.com/QLBQDVD.png)



## My results

* To deposit Sb on the Au Crystall of the UHV holder, I found out that the deposition is only working if the Au surface is prior to the experiment roughend.
* Discussion with Mr. B: suprising result, since it looks as if the deposition is diffusion limited. Hypothises of faster diffusion o a surface then in the bulk, that was also reported some time ago by Hubbard et al.
* My results are not in agrrement with the bulk Sb depostion of Da an Zan (on a single crystall).


**Typical CV (19.07.2019):**

![](https://i.imgur.com/811yZl9.png)


### XPS analysis of the deposited Sb layers

* Sb depostion for $t=90$ min to get a Sb layer with a neglegible Au signal in  spectra.
* a series of spectra is recordes after sputtering

**Survey spectra:**

![](https://i.imgur.com/Ex4sGjd.png)

* 50 eV resolution
* spectra only shows the Au, Sb, C and O  contribution
* After 90 min sputtering in total, the AU surface becomes clearly visble.


**high resolution Sb/O region (15 eV CAE):**

![](https://i.imgur.com/UVNZ0OQ.png)
![](https://i.imgur.com/9gycPZ4.png)
![](https://i.imgur.com/8u5w6eZ.png)
![](https://i.imgur.com/ufj8Y7j.png)

* deconvolution of the spectra is chellenging due to:
    * X-ray satelittes of the non monochomatic Mg source ($\alpha_3$, displacement 8.4 eV I=8% and $\alpha_4$ , displacement 10.1 eV I=4.1%)
    * humb after the peaks -> plasmon loss see [pollak1974]
* the following was considerered for the deconvolution of the Sb/O region:
    * 3d intensity ratios of the Sb peaks (3:2)
    * Area of O to fulfill chemcial structure of Sb2O3
    * Same G : L ratio for all peaks
    * Same FWHM for same  chemical nature
* Duiring sputtering the Sb(0) amount is increasing and the Sb(+III) ratio decreasing.
* After 90 min sputtering there is still some Sb(+III) left
    * This could also be an artfact out of diffrent sputtering rates for the diffent materials
* Sb(+III) is likley to be formed duiring air contact. Da Xings old measurements show, that the m.p.e. value of Sb formation. 
    * general idea: QMB experiment in which the m.p.e. value for the dissolution is measured after a certain time of air contact of the deposited Sb film.

**Atomic percenteges:**



| sputter time / min | Sb(0) | Sb(III) |
| -------- | -------- | -------- |
| 0     | 37.32     | 62.68     |
| 15     | 49.47     | 50.26     |
| 60     | 53.88     | 46.12     |
| 90     | 74.65     | 25.35     |



**Maybe the spectra need a new analysis due to the peak postion of the O1s signal. My evalutation: 530 eV, Literature: 531.5 eV**


### Measuring the amount of formed Sb(+III) in Potential step experiments

**General idea:** Sb(+III) will not contibute to the charge duiring the Sb desolution. The ratio between deposition and desolution charge is investigated after different electrode treatments: 

![](https://i.imgur.com/7TXVLRs.png)


**Results of the desolution process (normalized to the deposition charge):**

![](https://i.imgur.com/4DsnzMf.png)


**Results in a table:**

![](https://i.imgur.com/JwUe1mR.png)


### XPS analysis of the Mg deposition into Sb layers

#### CV in glovebox
![](https://i.imgur.com/h2IzfbM.png)

- Potential jump after two cycles

![](https://i.imgur.com/s48qVLv.png)

#### XP Spectra

![survey](https://i.imgur.com/43JHpKY.jpg)
![Mg](https://i.imgur.com/KKf8ObL.jpg)
![Al](https://i.imgur.com/q1iOUJW.jpg)
![Cl](https://i.imgur.com/0PZc5ws.jpg)
![C](https://i.imgur.com/Jt5yrlZ.jpg)
![Sb_O](https://i.imgur.com/A702hpc.jpg)





# Open questions

* diffrence between single crystall bulk deposition and my deposition. Why do I need a rough surface?
* Where is the Sb(+III) coming from? Can we show in an QMB measurement, that  it is formed duiring air contact?
    * Another way to show, that Sb(+III) is formed after Air contact colud be, just to measure the depostion/desolution current after air contact. 
* O1s peak position in the deconvolution



### Literature

[pollak1974] Journal of ELectron Spectroscopy and Related Phenomena, 3 (1974) 381-398!
