LONG-WAVELENGTH THRESHOLD OF Cs2O-COATED PHOTOEMITTERS

While Cs2O-coated III-V semiconductors can have Kelvin work functions as low as 0.7 eV, the long-wavelength threshold for efficient photoemission is determined by a significantly higher barrier at the heterojunction between the Cs2O and the semiconductor. This barrier is 1.23±0.03 eV for Cs2O on GaSb. For Cs2O on silver, the barrier height is 1.0 eV.