Electrical Interface Characterization of Ultrathin Amorphous Silicon Layers on Crystalline Silicon. Issue 2 (25th November 2020)

• Record Type: Journal Article
• Authors: Thoma, Patrick; Breyer, Evelyn Tina; Thoma, Oana‐Maria; Salvan, Georgeta; Zahn, Dietrich R. T.
• Is Part Of: Physica status solidi. Volume 218:Issue 2(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-11-25
• Subjects: a‐Si/c‐Si heterojunctions -- electrical measurements -- interface properties -- semiconductor heterojunctions -- solar cells; Solid state physics -- Periodicals; Solids -- Industrial applications -- Periodicals; 530.41
• DOI: 10.1002/pssa.202000079
• Languages: English
• ISSNs: 1862-6300

Abstract

Abstract : 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. Abstract : Heterojunctions of amorphous and crystalline silicon are prepared by radio frequency pulsed magnetron sputtering of p‐type amorphous silicon on p‐doped crystalline silicon wafers. During the sputtering process, the hydrogen flow rate is varied. Current–voltage measurements revealed different electrical conduction mechanisms, activation energies, barrier heights and conductivity depending on the ambient temperature and the hydrogen flow rate used.