ELECTRON-MOBILITY IN P-TYPE EPITAXIALLY GROWN CDXHG1-XTE

The minority carrier mobility is one of the fundamental material prope rties affecting the performance of Cd(x)Hg1-xTe detectors. It is also required directly to determine the steady state lifetime, which, when used in conjunction with the lifetime from transient photoconductive d ecay measurements, can lead to information on Shockley-Read traps. The measurement of electron mobility in p-type material is not straightfo rward and many different approaches have been tried. Our work has conc entrated on developing a model to predict the electron mobility in p-t ype Cd(x)Hg1-xTe. Two approaches have been considered. Firstly, the el ectron to hole mobility ratio (b) was investigated and secondly furthe r work was carried out using the semiempirical formula developed in a previous study. It was found that at temperatures above 200 K there wa s very little difference between the electron mobility in epitaxial p- type Cd(x)Hg1-xTe layers and that measured directly in n-type layers a nd good fits were obtained whichever method was used. At lower tempera tures the model developed in our previous study was seen to give the m ost consistent results, although introducing variations in b with temp erature led to improvements in the constant-b model below 200 K. The p redicted values have been used to determine the steady state lifetime.