Abstract
Optical properties of hydrogenated amorphous-siliconamorphous-silicon- nitride (a-Si:H/a-SiNx:H) superlattices (x=1.1) with a-Si:H sublayer thicknesses dS as small as 11 A have been investigated by photothermal deflection spectroscopy combined with the transmission and photoluminescence measurements. Changes in the optical band gap, Urbach energy, and defect-state absorption were observed for dS<30 A and studied in detail in order to clarify the origin of the size effects in these structures. In the lowest-thickness superlattices, the room-temperature luminescence consists of two emission bands at 1.3 and 1.46 eV, which we ascribe to hydrogen-rich and nitrogen-rich interfaces, respectively. The properties of these amorphous superlattices have been compared with those of hydrogen-rich a-Si:H deposited at low temperatures and a-SiNx:H alloys (0<x<1.1) contaminated deliberately by nitrogen.
Original language | English |
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Pages (from-to) | 8837-8841 |
Number of pages | 5 |
Journal | Physical Review B |
Volume | 37 |
Issue number | 15 |
DOIs | |
Publication status | Published - 1988 |
Externally published | Yes |