Studies on Carrier Transport Through a-Si:H/a-Si1−xCxH Quantum Well Structures Imbedded in the i Layer of a p-i-n Structure

Abstract

ABSTRACTa-Si:H/a-Si1−XCX:H single and double barrier structures imbedded at different locations of the i layer of a p-i-n structure were used to study the carrier transport properties of amorphous QW. The shapes of the observed I-V curves of both structures are similar. The bound states of the well layer of double barrier structures do not play a role in the carrier tunneling process. The resonant tunneling time is larger than the inelastic scattering time by 5 to 12 orders of magnitude. When the tunneling process of amorphous QW is in the completely incoherent tunneling regime, the peak-to-valley ratio of NDR and the density of states in the well go to zero. From the analysis of I-V characteristics of both structures under different monochromatic light illumination, the observed current dips are due to the collection of photogenerated carriers in two regions of the i layer separated by the imbedded barrier structure.