Photoemission from K–Te photocathodes

Abstract

In this letter the photoemissive properties of K-Te films produced under ultrahigh vacuum conditions are reported. K-Te photocathodes were fabricated by vapor deposition of Te and K onto a Mo substrate into the preparation chamber of the Free Electron Laser of the University of Twente. The highest quantum efficiency obtained at 259 nm was 11.1%, measured just after evaporation; this value decreased in a few minutes to a stable quantum efficiency of 8.3%. The reported results show that K-Te can be considered a promising material for the use as a photocathode in photoinjectors.

K–Te photocathodes: A new electron source for photoinjectors

“…Details concerning the preparation procedure can be found elsewhere. 5 A mercury lamp with different bandpass interference filters has been used to illuminate the photocathode ͑biased by Ϫ90 V͒ with light of different wavelengths, in order to measure the photocurrent with a picoammeter. The optimized Te evaporation time already determined in previous investigations 5 has been used for the preparation of all the cathodes reported in this article.…”

“…Recently, we have demonstrated the photoemissive properties of K-Te semiconductor films evaporated under ultrahigh vacuum ͑UHV͒ conditions. 5 Their high QE at 259 nm and long lifetime after storage in UHV conditions, have suggested the possibility of using K-Te films as photocathodes in electron accelerators. We have verified this possibility, operating the electron accelerator of the Twente FEL with K-Te photocathodes and investigating both their lifetime under operating conditions and their regeneration by substrate heating.…”

FP-LAPW investigation of mechanical and thermodynamic properties of Na2X (X = S and Se) under pressure and temperature effects

“…Apart from being used in power sources, fuel cells, gas-detectors and ultra violet space technology devices [4][5][6], these ionic compounds also play an important role in the development of photocathodes, in supporting catalytic reactions and enhancing oxidation of semiconductor surfaces [7][8][9][10][11][12][13][14].…”

First Principles Study of Mechanical Stability and Thermodynamic Properties of K2S under Pressure and Temperature Effect

“…At zero pressure and 300 K, the thermal expansion α is 7.03 × 10 −5 K. The entropy S under high pressure and high temperature can be obtained according to Eq. (12). Figure 7 shows the curve of entropy S at different pressure and temperature.…”

“…The alkali metal chalcogenide K 2 S are characterized by their high ionic conductivity [3][4][5] and they exhibit large electronic band gaps. Apart from being used in power sources, fuel cells, gas-detectors and ultraviolet space technology devices [6][7][8], these ionic compounds also play important role in the development of photocathode, in supporting catalytic reactions and enhancing oxidation of semiconductor surfaces [9][10][11][12][13][14][15][16], and therefore are ideal for theoretical and experimental studies.…”