SUBMILLIMETER-WAVE LOW-TEMPERATURE ADMITTANCE OF N-GAAS AND N-INP DIODE STRUCTURES

Numerical simulation results for n+nn+ GaAs and InP diode structures i n the 1-5 THz frequency range are presented. Cryogenic temperatures fr om 4 through about 77 K as well as some cases above liquid-nitrogen te mperature are examined to obtain the two-terminal admittance. Earlier work has suggested possible negative conductivity at or below 4.2 K, b ut nothing consistent above 77 K. Implications of the Monte Carlo data for generation of submillimeter waves at intermediate lattice tempera tures between 4 and 60 K are discussed for GaAs. Furthermore, numerica l results are obtained at elevated lattice temperatures (200 and 300 K ) to form a more complete view of transport in InP. The GaAs and InP r esults strongly suggest negative conductance behavior will be found be low 20 K.