The ultraviolet photovoltaic response of barrier‐layer cells formed from single‐crystal rutile has been investigated. Typical samples have response maxima at 3200 Å, aD* of 109cm cps1/2/W, and time constants of 100 &mgr;sec. Variations in time constant over several orders of magnitude have been observed, dependent largely on preparative technique. The effect of surface treatment on cell characteristics is discussed.