This thesis deals with electrical and optical characterization of p+i–n+ nanowire-based photodetectors/solar cells. I have investigated their I-V performance and found that all of them exhibit a clear rectifying behavior with an ideality factor around 2.2 at 300K. used Fourier transform infrared spectroscopy to extract their optical properties. From the spectrally resolved photocurrent data, I conclude that the main photocurrent is generated in the i-segment of the nanowire (NW) p-i-n junctions, with negligible contribution from the substrate. I also used a C-V technique to investigate the impurity/doping profiles of the NW p+-i-n+ junction. The technique has been widely used for investigations of doping profiles in planar p-n junctions, in particular with one terminal (n or p) highly doped. To verify the accuracy of the technique, I also used a planar Schottky sample with an already known doping profile for a test experiment. The result is very similar to the actual data. When we used the technique to investigate the doping level in the NWs photodetectors grown on InP substrates, the results show a very high capacitance above 800pF which most likely is due to the influence of the parasitic capacitance from the insulating layer of SiO2. Thus, a new sample design is required to investigate the doping profiles of NWs.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:hh-25733 |
| Date | January 2014 |
| Creators | Dawei, Jiang |
| Publisher | Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE) |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
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