We demonstrate the minority carrier lifetime measurements of polycrystalline silicon nanowires (poly-SiNW) films passivated with aluminum oxide (Al2O3) deposited by atomic layer deposition (ALD). The poly-SiNW films were prepared by metal-assisted chemical etching of poly-Si films. The poly-Si films were prepared by solid phase crystallization of a-Si films deposited by radio-frequency sputtering on aluminum induced crystallized poly-Si template. The deposition of an ALD-Al2O3 passivation layer and subsequent annealing enabled us to measure effective minority carrier lifetime of the poly-SiNW films. The effective lifetime was found to be 5.76 μs. This result indicates that ALDAl2O3 is beneficial to surface passivation of poly-SiNW films.
Polycrystalline silicon nanowires (poly-SiNWs) films were successfully prepared by using metal assisted chemical etching of polycrystalline silicon (poly-Si) films. The poly-Si films were prepared by solid-phase crystallization of amorphous silicon (a-Si) deposited by different deposition techniques on different substrates. In the case of the electron beam evaporated a-Si on a quartz substrate, the formation of poly-SiNWs was not observed and the structure was found to be porous silicon. On the other hand, poly-SiNWs successfully formed from poly-Si on a silicon substrate. We also found that deposition techniques for a-Si films affect the formation of poly-SiNWs.
The effect of tapered shape on electrical properties of heterojunction silicon nanowire (SiNW) solar cells was simulated with a two-dimensional quantum device simulator. When the quantum effect was taken in account, opencircuit voltage (Voc) and fill factor (FF) of heterojunction SiNW solar cells were drastically improved from 390 to 862 mV and from 0.662 to 0.795, respectively. This is due to the bandgap widening and the enhancement of electric field in the intrinsic SiNW. When a top side diameter (d1) of the SiNW was set at 2 nm and a bottom side diameter (d2) was varied from 2 to 6 nm, short-circuit current density (Jsc) was drastically increased from 6.96 to 30.8 mA/cm2. The main reason is the absorption enhancement due to a tapered shape with a graded refractive index. Ultimately, conversion efficiency was monotonically increased with increasing d2 in the range from 2 to 6 nm. The quantum size effect and the tapered shape can enhance conversion efficiency of heterojunction SiNW solar cells.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.