This paper is dedicated lo Professor Camille Srrrzrlor/y 011 rlze occrrsiorr of his 65111 birrhrlayHIROsHl TSUBOMURA, YOSHIHIRO NAKATO, MASAHIRO HIRAMOTO, and HIROYUKI YANO. Can. J. Chem. 63, 1759Chem. 63, (1985. Photoelectrochemical propcrties of p-'-n junction silicon electrodes, abbreviatcd as p+n-Si, coated with thin oxide films of titanium, tungstcn, or iron have been investigated in aqueous solutions of hydrogen iodide and iodine. The films were deposited by electron-beam evaporation of the mctal oxide sinters. The photocurrent in a p'n-Si elcctrodc coated with TiO' increased dramatically when it was heatcd at temperatures highcr than 500°C, though the O/Ti atomic ratio as determined by ESCA analysis was unchanged. The fill factor of the photovoltaic cell composcd of this clcctrode, a platinum counter electrode and an aqueous solution of 7.6 M HI and 0.03 M 1' was improvcd by coating with ruthcnium or its oxide. Thc photovoltaic cell attained a high solar to electrical cnergy convcrsion efficiency of 9.3% (AMI), with an opcn circuit photovoltage of 0.58 V , a short circuit photocurrcnt of 26.6 mA cm-' and a fill factor of 0.61. The photocurrent was stable for 350 h. For the cases of electrodes coated with a FczO, or WO, film. high fill factors were obtained evcn without ruthenium coating. Thc effect of the nature of Si -metal oxide junctions, the donor density in the oxide, the relations between the flat band potential of the oxide and the redox potential of the solution, etc., on the conversion efficicncy was discussed.HlRos~l TSUBOMURA, YOSHIH~RO NAKATO, MASAHIRO HIRAMOTO et HIROYUKI YANO. Can. J . Chcm. 63, 1759 (1985). Optrant dans des solutions aqueuscs d'iodurc d'hydrogene et d'iode, on a CtudiC Ics proprittts phototlcctrochimiqucs d'tlectrodes de silicium, a jonction p+-n rcprksentCes par p 'n-SI, recouvertes dc minces couches d'oxydes dc titane, de tungstkne ou de fer. On a dtpost les films en faisant appel i I'dvaporation par faisceaux d'dlectrons dc frittages d'oxydes de mCtaux. Le courant photoClectrique de I'Clectrode p+n-Si sur laquelle on a dtposd du TiOl augmcnte d'une f a~o n dramatique lorsqu'on la chauffe i des temptraturcs suptrieurcs h 500°C; on obtient ce rCsultat meme si le rapport atomlque dc O/Ti, tcl que dCtermint par une analysc ESCA, dcmeure inchange. Le facteur de remplissage dc la cellule photovoltai'que composte de cette tlectrode, d'une contre-dlcctrode de platine et d'une solution aqueuse 7,6 M cn HI ct 0,03 M en I? augmente si I'on y dCposc du ruthCnium ou son oxyde On peut atteindre un haut dcgrd (9,3% AMI) d'cfficacitd pour la conversion de I'tnergie solaire en tncrgie Clcctrique SI I'on opkre avcc un photovoltage en circuit ouvcrt de 0,58 V , un photocourant dc court circuit de 26,6 m~c m -' et un facteur de rcmplissage dc 0,61. Le photocourant s'cst avdrd stable pour 350 h. Dans les cas des Clectrodes sur IesqueIles on a dCposC dcs films de FeZO, ou de WO,, on a pu obtenir des factcurs dc remplissage tlevds sans mCme dCposer du ruthenium. On discutc dc I'cffct de la n...