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Electrical Interface Characterization of Ultrathin Amorphous Silicon Layers on Crystalline Silicon
Author(s) -
Thoma Patrick,
Breyer Evelyn Tina,
Thoma OanaMaria,
Salvan Georgeta,
Zahn Dietrich R. T.
Publication year - 2021
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.202000079
Subject(s) - materials science , silicon , crystalline silicon , arrhenius plot , amorphous silicon , amorphous solid , activation energy , wafer , nanocrystalline silicon , heterojunction , optoelectronics , analytical chemistry (journal) , sputter deposition , monocrystalline silicon , sputtering , thin film , nanotechnology , crystallography , chemistry , organic chemistry , chromatography
Heterojunctions of amorphous (a‐Si) and crystalline (c‐Si) silicon combine the favorable absorption characteristics of a‐Si for the solar spectrum, high energy conversion efficiencies, low processing temperatures, potential for low production costs, and a reduced amount of silicon used due to thin a‐Si films. To investigate a‐Si/c‐Si heterojunctions, amorphous p‐type silicon (a‐Si) with a thickness of 5 nm is deposited via radio frequency‐pulsed magnetron sputtering on p‐doped, (100)‐oriented, crystalline silicon (c‐Si) wafers. During deposition, the crystalline silicon wafers are kept at 430 °C and the hydrogen flow rate is varied from 0 to 50 sccm (standard cubic centimeters per minute). Temperature‐dependent current–voltage measurements are carried out to investigate the dominant transport mechanisms of electrical conduction. Moreover, the influence of hydrogen on physical properties such as barrier height, activation energy, and electrical conductivity is analyzed. A current–voltage dependence as predicted by the thermionic emission model for the low forward‐bias region below 0.25 V is observed. Temperature regimes for nearest neighbor hopping and band conduction are revealed by the Arrhenius plot and are found to depend on the hydrogen flow rate.