A study of electrical properties on nc-Si/c-Si heterojunction diodes

Nanocrystalline silicon films on crystalline silicon diodes were fabricated and electrically characterized. The nc-Si:H film was deposited by plasma enhanced chemical vapor deposition. With the difference of the thickness of the nc-Si:H film and the doping type of the c-Si substrate two kinds of diodes, tunneling diodes and heterojunction diodes, were formed. For the tunneling diode, resonant tunneling and quantum staircases were observed in its I-V and σ-V curves in liquid nitrogen temperature range (~77 K). For heterojunction diodes, we found some unique characters differing from other semiconductor heterojunctions. Both of these devices indicate quantum tunneling features in the conduction mechanism