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用温度T_φ分别为77°K和300°K的黑体,照射液氮冷却的合金型和扩散型锑化铟光电二极管,研究了它们的噪声,并在20赫～20千赫的范围内,对有正、反偏压的二极管作了测量。研究表明,这两种类型的二极管因有偏压,而存在过剩噪声,这种过剩噪声是由欧姆漏电流的起伏而引起的,并且随着T_φ中的升高而增大。因此,不同的二极管有不同的噪声特性。合金型二极管噪声频谱的形式为S_i～f~(-1),其中S_i是电流噪声的频谱密度,f是频率,而且S_i值对可见光的照射是很敏感的。有时,这部分频谱随着f的增高而转变为S_i～f~(-0.5)的另一谱段。在研究的整个频率范围内,扩散型二极管噪声频谱的形式为S_i～f~(-0.5),S_i值与光照无关。虽然扩散型二极管的漏电导相当大,但是合金型二极管的这种噪声电平,比扩散型二极管的要高得多。这就表明,在零偏压时,不论在T_φ=77°K或T_φ=300°K,合金型二极管的最小噪声电平要比扩散型二极管的低,而扩散型二极管的这种噪声电平,在这两种温度下,都与热噪声电平相一致,但合金型二极管的这种噪声电平仅在T_φ=300°K时才与散粒噪声相符合。
Using a blackbody with T_φ of 77 ° K and 300 ° K respectively, a liquid nitrogen-cooled alloyed and diffused antimony indium antimonide photodiode was irradiated, their noise was studied, and in the range of 20 Hz to 20 kHz, Positive and negative bias diodes were measured. Studies have shown that these two types of diodes are biased due to excess noise, which is caused by the fluctuation of the ohmic leakage current and increases as the T_φ increases. Therefore, different diodes have different noise characteristics. The alloyed diode noise spectrum has the form S_i ~ f ~ (-1), where S_i is the spectral density of the current noise, f is the frequency, and S_i is sensitive to visible light exposure. Sometimes, this part of the spectrum with the increase of f into S_i ~ f ~ (-0.5) of another spectrum. In the study of the entire frequency range, the diffusion of the diode noise spectrum in the form of S_i ~ f ~ (-0.5), S_i value and light has nothing to do. Although the diffused diode has a relatively large leakage conductance, the noise level of the alloyed diode is much higher than that of a diffused diode. This shows that at zero bias, the minimum noise level of the alloyed diode is lower than that of the diffused diode, at T_φ = 77 ° K or T_φ = 300 ° K, whereas this noise level of the diffused diode At both temperatures, it is consistent with the thermal noise level, but the noise level of the alloyed diode matches the shot noise only at T_φ = 300 ° K.