The Deep 0.11eV Manganese Acceptor Level in GaAs
- PDF / 325,674 Bytes
- 4 Pages / 420.48 x 639 pts Page_size
- 68 Downloads / 169 Views
THE DEEP 0.11eV MANGANESE ACCEPTOR LEVEL IN GaAs M. KLEVERMAN*, E. JANZ fN*, M. LINNARSSON*#, B. MONEMAR** *Lund University, Dept. of Solid State Physics, S-221 00 LUND, Sweden **Link6ping University, Dept. of Physics and Measurement Technology, S-581 83 LINKOPING, Sweden ABSTRACT The 0.11 eV Mn acceptor has been investigated using different kinds of FTIR techniques, Zeeman spectroscopy, and photoluminescence. The results clearly fits into the 3d 5 + shallow hole model for Mn 0 and show that the 0.11 eV level originates from the ionization of a neutral, substitutional Mn acceptor at a Ga-site. The ground state binding energy obtained from the effective-mass like excited states is 112.4 meV. INTRODUCTION Manganese as a dopant in GaAs gives rise to an acceptor level about 0.11eV above the valence band. The level has been observed by Hall measurements [1], photoluminescence [2,3], absorption [4] and by space charge techniques [5]. EPR measurements showed a spectrum characteristic for 55Mn with nuclear spin 5/2 [6,71. The hyperfine interaction was found to be isotropic. The fine structure lines which are influenced by the 3d electrons were not resolvable. Atomic manganese has the electronic configuration (Ar) 3d 5 4s 2. On a substitutional Ga site three electrons would be used for the bonds to the nearest As atoms leaving the the neutral manganese atom in a 3d 4 configuration. Alternatively, it may be favorable energetically to form a 3d 5 (Mn-)5 + loosely bound hole configuration. Recent EPR [8] and MCD [9] results favor the 3d configuration.
In this paper we will present absorption and photoconductivity data showing excited states of a neutral acceptor in great detail. The binding energy is 112.4 meV. The Zeeman data to be presented clearly favors the shallow hole model. EXPERIMENTAL The sample preparation is described in detail in Ref. 13, concerning Cu doped GaAs and only details specific for the fabrication of the Mn samples will be described here. Crushed manganese lumps and crushed GaAs wafers were mixed and put into a quartz ampoule together with the GaAs wafer. The samples were diffused at temperatures from 700 to 800 'C for 2-5h. After diffusion the ampoules were allowed to cool in the furnace or quenched in air. Both sides of the wafers were polished about 10 pm and then slightly etched 1pm. About 500 pm were polished away form the surfaces of the samples used for the Zeeman experiments.
The SIMS data were obtained using 0+ions. As reference we used a sample - 250 keV and a dose of 5x10 14 cm'2.
55
Mn-implanted
EXPERIMENTAL RESULTS AND DISCUSSION Non-perturbation data In Fig. 1 typical photoluminescence spectrum of a Mn-diffused sample is shown. The diffusion was carried out at 800 'C for 2h 40 min. The carrier concentration measuMat. Res. Soc. Symp. Proc. Vol. 163. 91990 Materials Research Society
208
red with a Polaron Profi-
ler was lx10 18 cnm3 and was equal to the total Mn concentration as measuT=2K red with SIMS. However, the SIMS data showed . that 100 pnm below the surface the Mn concentrati
Data Loading...
