Peculiarities of relaxation processes in Cd1-xMnxTe crystals
|Zinaida Zakharuk 1, Eugene Nikonyuk 2, Vasyl Shlyakhovyi 2, Mykola Kuchma 2, Anna Rarenko 1, Ivan Yurijchuk 1|
1. Chernivtsi National University (ChNU), 2 Kotsubinsky Str., Chernivtsi 58012, Ukraine
Optical and electrophysical properties of Cd1-xMnxTe crystals (0,2<x<0,5) grown by Bridgeman method have been studies. It was found that hole conductivity of the crystals is controlled by A2 (ε=0,12 eV) or A3 (ε=0,2 eV) acceptors, and shallow A1 acceptors are completely compensated. Besides, a tendency to increasing of crystal specific resistance ρ with increasing of manganese content x was detected. The dependence of specific resistance on x is approximately linear so as the dependence of acceptor ionization energies. Solid solution crystals at x<0,06 demonstrated stable and reproducible electric characteristics at heating up to 420 K. But at x>0,06, when A3 acceptors contribution into conductivity becomes significant, the "hyzteresis" type relaxation processes in the temperature region from 290 K to 420 K were observed. Note, that hole mobilities do not relax and therefore the change of ρ is caused by the change of hole concentration only. Isothermal changes of hole concentration in the limits from half an order to three orders take place in this case depending on solid solution composition over a period of several hours. The relation of specific resistances at points of isothermal change of ρ has the highest values for samples maiden from section of growing ingots with maximal residual impurity concentration. Thus, one can suppose that the relocalization of residual impurities like copper according to "site-interstitial" mechanism can be involved in the relaxation processes.
Presentation: poster at E-MRS Fall Meeting 2004, Symposium F, by Zinaida Zakharuk
See On-line Journal of E-MRS Fall Meeting 2004
Submitted: 2004-04-29 14:48 Revised: 2009-06-08 12:55