Excess Noise in Germanium and Gallium‐Arsenide Esaki Diodes in the Negative Resistance Region

摘要

Low‐frequency noise measurements have been made throughout the entire useful bias range of germanium and GaAs Esaki diodes. Evidence is presented in agreement with Esaki and Yajima that a near square‐law relationship exists between the mean‐square, short‐circuit noise current and excess current for bias voltages beyond the valley voltage in germanium diodes. Attempts to find a like relationship in GaAs were not conclusive. Measurements of the noise within the negative‐resistance regions of the diodes showed a nearly continuous exponential relationship between excess noise and bias for the germanium units and a similar plot was obtained for the GaAs diodes, except a well‐defined peak in the noise current was found at about 0.2 v forward bias. The evidence that the results indicate a rather continuous distribution of allowed states in the forbidden band of the germanium samples and a possible localized maximum in these states in the GaAs samples is discussed.