Regensburg 1998 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

HL: Halbleiterphysik

HL 19: II-VI Halbleiter

HL 19.13: Vortrag

Dienstag, 24. März 1998, 19:00–19:15, H16

A study of deep centers in Zn_1−xMg_xSe — •R. Beyer¹, H. Burghardt¹, F. Firszt², and D.R.T. Zahn¹ — ¹Institut f"ur Physik, Professur f"ur Halbleiterphysik, Technische Universit"at Chemnitz, D-09107 Chemnitz — ²Institute of Physics, University of Torun, Grudziadzka 5-7, 87-100 Torun, Poland

Deep centers in Zn_1−xMg_xSe (x=0.09, 0.15) were studied by Deep Level Transient Spectroscopy in the temperature range between 77 K and 400 K. Samples were obtained by the high pressure Bridgman method from the melt under argon pressure of 11 MPa using a mixture of ZnSe powder, Mg and Selenium. The crystals were cut and annealed in Zn vapour for 48 h. Temperature and frequency dependent IV and CV measurements of Au/Zn_1−xMg_xSe Schottky contacts were performed. A doping concentration of 2x10¹⁶cm⁻³ was determined. A dominating electron trap was found with a thermal activation energy E_tA= 0.37 (Mg content x=0.09) and 0.38 eV (x=0.15) and a trap concentration approximately 2 orders of magnitude below the doping concentration. We correlate this level to the well known 0.32 eV center (Se vacancy) in ZnSe. In order to study the capture behaviour of the trap, isothermal capacitance transient spectroscopy with filling pulse variation from 10 ns to 1 s was used, providing information about the activation energy of the capture process and the capture coefficient as well.