Theoretical modeling and structural characteristics analysis of optical and electric injected AlGaAs/GaAs NEA arrays cathode

In order to obtain high emission current efficiency of the AlGaAs/GaAs NEA array cathode, this array cathode has two ways of optical injection and electrical injection to form electron emission. Based on the two-dimensional continuity equation of electronic transport in the variable bandgap emission array, the finite volume method is used for numerical solution and simulation to obtain the emission current and emission current efficiency. Simulation obtains the optimal parameter range for each layer of the AlGaAs/GaAs NEA array cathode under both optical and electrical injection scenarios. The results show that the optimal angle of incident light for the array cathode under light injection is 10°-30° for selecting an array micro-nano column with a duty cycle of 2/3. Under the condition of light injection, the P-type variable bandgap AlGaAs layer array micro-nano column height ranges from 0.3-0.6 μm. Under the condition of electrical injection, the height of the micro-nano column of the P-type variable bandgap AlGaAs layer array is 0.1-0.3 μm. The optimal thickness range of N-type variable bandgap AlGaAs layer, N-type AlGaAs layer, and P-type AlGaAs layer under light injection is 0.5-2.5μm, 0.5-1μm and 0.2-0.5μm, respectively. The optimal thickness range of N-type variable bandgap AlGaAs layer, N-type AlGaAs layer, and P-type AlGaAs layer under electrical injection conditions is 2-3μm, 0.8-1.2μm and 0.1-0.3μm, respectively. The optimal doping concentrations of P-type AlGaAs layer and N-type AlGaAs layer under light injection range from 5×10¹⁸-1×10¹⁹ cm^-3 and 1×10¹⁸-5×10¹⁸ cm^-3, respectively. The optimal doping concentrations of the P-Type AlGaAs layer and the N-Type AlGaAs Layer under electrical injection range from 1×10¹⁸ to 5×10¹⁸ cm^-3 and 5×10¹⁷ to 1×10¹⁸ cm^-3, respectively. The maximum efficiency of the emission current under the light injection is 35.04%, and the maximum emission current per unit length is 10.3nA/μm. The maximum efficiency of the emission current under electrical injection is 31.23%, and the maximum emission current per unit length is 105.5uA/μm. Electrical injection cathode does not need expensive and complex drive laser system, light injection control mode is simple, light injection or electrical injection control mode can be chosen as needing. This integration of a variety of advanced technology advantages of the array cathode research, for enriching the cathode array cathode emission theory, expanding its application field is of great significance.