Pumping of GaAs1−x Px : N (at 77 °K, for x≲0.53) by an electron beam from a gas plasma

The design features and operating parameters of a cold‐cathode gas plasma electron beam apparatus for bombardment excitation of semiconductor samples is described. The gas plasma apparatus is capable of electron beam energies > 50 keV and current densities ≳50A/cm², which are sufficient for semiconductor laser operation. Although photopumping and high surface losses do not permit the observation of an A‐line peak in $\text{0.4<x≲0.8\hspace{0.17em}}{\mathrm{GaAs}}_{\text{1−x}}{\mathrm{P}}_x:{\mathrm{N}}^{+}(\mathrm{N}{\text{>10}}^{19}/{\mathrm{cm}}^3)$ , the deeper pumping of the gas plasma electron beam source permits observation of the A‐line, as is demonstrated on x = 0.53 material. The deeper excitation afforded by the gas plasma electron beam apparatus, and lower over‐all surface losses have permitted laser operation of indirect crystal (x > x_c) made quasidirect by the N trap, as is shown (77 °K) on the A‐line transition in x = 0.47 (x > x_c ≈ 0.46) GaAs_1‐x P_x : N⁻ (N < 10¹⁹/cm³).