I've been looking at HEMT to use at low temperatures.
GaAs and GaN seem to be discussed often in the context of low temperature amplification.
My questions are twofold.
To be suitable for low temperature operation, is it about having a small ionization energy value for electrons to break free?
For low temperature operation, I naturally care about the transistors' power dissipation. I looked at the datasheet of ATF33143 (GaAs pHEMT) and it says its power dissipation is 600mW whereas the datasheet of CG2H40025 (GaN HEMT) does not seem to say anything about its power dissipation. It does mention "Saturated Power Output" as 6W, which I think is different. How does one go about finding the power dissipation? Is it just Idss*Vds? For ATF33143, Idss = 300mA, which was measured at Vds = 1.5V, which would give about 450mW, at least on the same order of magnitude as the power dissipation of 600mW given in the datasheet.