Light and thermally induced metastabilities in electrochemically etched nanocrystalline porous silicon

N P Mandal , Manohar Awasthi (1) , Aniruddha Konar (2) , Abhishek Kumar (3) , Dudhnath Patel (4)

1 Physics
2 Physics
3 Department of Physics and Applied Physics [Lowell]
4 Department of Physics [Kanpur]

We observe that light soaking for short durations and thermal quenching in nanocrystalline porous silicon (PS) produce metastable states. These metastable states show higher dark current, higher and photo current, large photoluminescence and weaker electron spin resonance (ESR) signal. However, long exposures to light produce opposite effect. The metastable states are stable against sub band gap light exposures. These metastable states can be removed by annealing at 150 0C for 1 hour. ESR shows the presence of a-Si phase (g~2.0058, 6.4G) in PS sample, but it is not sufficient to explain all experimental results. Rather, our experiments suggest that light soaking causes more than one type of defects in porous silicon. The structural changes involving the movement of hydrogen present at the surface of PS or at PS/a-Si interface may be responsible for these effects.

Mots clés: Physical Sciences

N P Mandal, Manohar Awasthi, Aniruddha Konar, Abhishek Kumar, Dudhnath Patel. Light and thermally induced metastabilities in electrochemically etched nanocrystalline porous silicon. Philosophical Magazine, 2009, 89 (04), pp.311-321. ⟨10.1080/14786430802620716⟩. ⟨hal-00514005⟩