Hydrogen-doped indium oxide (IO:H) layers with very high carrier mobility have been developed by two-step fabrication procedure. In the first step IO:H films were deposited by radio frequency (RF) magnetron sputtering from In2O3 target in Ar/water vapour gas mixtures. Different sputtering powers and partial pressures of H2O (pH2O) have been explored and effects induced by changes of these process parameters on final film structure and on electro-optical properties have been investigated. In the second step a post-deposition annealing under vacuum were performed. During this treatment a complete and complex amorphous-crystalline transition occurred. Growth of large crystalline domains give rise to IO:H films with excellent carrier mobility values, up to 138 cm2/Vs. For each sputtering power used, the pH2O range has been identified which allows to obtain the highest carrier mobility value for IOH post-annealed films. Growth of large crystallites occurred in IO:H annealed films and, at this purpose, a selective chemical etching method has been developed to give better evidence for the polycrystalline grains. IO:H films appeared formed by fairly large crystalline domains with presence of sub-grains. Silicon heterojunction cells fabricated by using IO:H layers as front electrode, compared with those obtained from a conventional ITO showed improved short-circuit current density and the resulting conversion efficiency.
Hydrogen-doped In2O3 for silicon heterojunction solar cells: Identification of a critical threshold for water content and rf sputtering power
Addonizio, M. L.;Spadoni, A.;Antonaia, A.;Usatii, I.;Bobeico, E.
2021-01-01
Abstract
Hydrogen-doped indium oxide (IO:H) layers with very high carrier mobility have been developed by two-step fabrication procedure. In the first step IO:H films were deposited by radio frequency (RF) magnetron sputtering from In2O3 target in Ar/water vapour gas mixtures. Different sputtering powers and partial pressures of H2O (pH2O) have been explored and effects induced by changes of these process parameters on final film structure and on electro-optical properties have been investigated. In the second step a post-deposition annealing under vacuum were performed. During this treatment a complete and complex amorphous-crystalline transition occurred. Growth of large crystalline domains give rise to IO:H films with excellent carrier mobility values, up to 138 cm2/Vs. For each sputtering power used, the pH2O range has been identified which allows to obtain the highest carrier mobility value for IOH post-annealed films. Growth of large crystallites occurred in IO:H annealed films and, at this purpose, a selective chemical etching method has been developed to give better evidence for the polycrystalline grains. IO:H films appeared formed by fairly large crystalline domains with presence of sub-grains. Silicon heterojunction cells fabricated by using IO:H layers as front electrode, compared with those obtained from a conventional ITO showed improved short-circuit current density and the resulting conversion efficiency.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
