Diode detectors (DD) are widely used in electronic information and communication systems. The use of diodes with Schottky barrier gave a possibility to master radiowaves of high frequencies (above 1 GHz). These diodes use the quick-acting metal-semiconductor contacts. The further improvement of their parameters was achieved due to fall of the working temperature (T). This direction was named cryogenic electronics or briefly cryoelectronics, it allows to raise the nonlinearity of the current-voltage dependences (CVD) and current responsivity (CR). In this paper the numerical modeling of the electrical potential distribution and current passing in the contacts of normal metal with semiconductor alloy bismuth-antimony (Bi-Sb) with different contact area was made. There were analyzed possibilities to create the diode detectors based on these contacts and working at liquid helium temperature 4.2 K. The dependences of the current responsivity, the voltage responsivity (VR) and the noise equivalent power (NEP) on the signal frequency (f) were analyzed. The obtained results were compared with literature data. Both DD working at temperature of liquid nitrogen (T = 77.4 K) and liquid helium (T= 4.2 K) were considered. The comparison with existent literature data shows the proposed DD can be 10100 times better. The physical reasons of these advantages were discussed too. It is shown that unique properties of Bi-Sb alloys and especially of Bi0.88Sb0.12 alloy make these alloys to be the very perspective materials for cryoelectronics. Therefore these DD are perspective for cryogenic electronics and there is an actual problem to elaborate them.