Albert Juma

11 Questions 15 Answers 0 Followers

Questions related from Albert Juma

How good are carbon contacts for MIS structures compared with other metal contacts like Ni, Au and Al?

To perform electrical measurements on thin film devices, we always need ohmic metallic contact electrodes. The most commonly used metals are Au and Al. I would like to use carbon paste but I have...

10 November 2014 1,841 4 View

Are all metal acetylacetonate precursor salts soluble in ethanol?

I want to deposit zirconium oxide by spray pyrolysis. I am not a chemist and I need the advice of chemists out there. Is zirconium acetylacetonate soluble in ethanol? I found that it is soluble...

31 October 2014 9,262 4 View

How does the bias voltage affect/influence impedance properties of a MOS structure?

I have done impedance measurements of a metal-oxide-semiconductor structure as a function of the bias voltage. The radius of the impedance arc in the Nyquist plot decreases with and increase in...

11 October 2014 3,562 2 View

How can I calculate film thickness and refractive index from UV-vis reflectance and/or transmittance data only, without interference fringes?

For thicker homogeneous films, the optical reflectance and transmittance spectra show several interference patterns which can be used to obtain optical constant using Swanepoel and other related...

09 October 2014 6,500 10 View

Is it possible to measure transistor output and transfer characteristics using Autolab setup?

I am preparing to start working on thin film transistor (TFT) devices from metal oxides. In literature I have seen most people use semiconductor parameter analyzers for measuring drain current as...

19 September 2014 474 4 View

How is the droplet size in an aerosol in a spray pyrolysis experiment calculated?

I sprayed my samples by nebulizing/atomizing a precursor solution of InCl3 salt dissolved in ethanol solvent. I would like to know the size of the aerosol droplet. Is there a way of calculating...

22 January 2014 1,000 5 View

Why are indirect semiconductors used as absorbers in solar cells despite their inferior absorption coefficient compared to direct semiconductors?

How does the nature of the band gap (direct or indirect) affect the efficiency of a solar? Recombination processes must be different for solar cells made from these solar cells, how does this...

26 November 2013 6,169 6 View

Which organic solvents can be used to disolve PbI2 or PbCl3 crystals?

We would like to find a suitable solvent for lead iodide (PbI2) that can be nebulized easily for deposition by spray pyrolysis. PbI2 is soluble in DMF(N,N-dimethylformamide) but this is not good...

14 October 2013 6,489 4 View

What is a metallurgical heterojunction?

I know about abrupt and graded heterojunctions and have read about metallurgical junctions but I have not seen a good example of a metallurgical heterojunction. For example, how can one explain a...

25 August 2013 3,319 3 View

How does the stoichiometry of a host semiconductor affect diffusion of a foreign atom?

I am investigating diffusion of Cu in In2S3 layers with and without chlorine and the activation energies and pre-exponential factor D0 are different for the two sets of layers. Structural...

22 April 2013 6,553 8 View

How can one determe the ionization potential directly using UPS/XPS? Is it possible to show this directly on the UPS/XPS spectra? If so, then how?

I know ionization potential can be obtained by adding the work function to the valence band maximum, which can be both determined directly from a UPS/XPS spectra. I was wondering if this is...

12 April 2013 1,166 5 View