Steady-state and time-resolved photoconductivity measurements of minority carrier lifetime in ZnTe
- Materials Science Centre, Indian Institute of Technology, Kharagpur 721302 (India)
- National Renewable Energy Laboratory, Golden, Colorado 80401 (United States)
Minority carrier lifetime in ZnTe has been determined from steady-state and time-resolved photoconductivity (PC) measurements. Three types of single crystal p-ZnTe&hthinsp;(E{sub G}=2.26&hthinsp;eV) grown by the Bridgman technique were studied: (i) as-grown, before and after hydrogen passivation, (ii) Zn annealed, and (iii) In-doped semi-insulating. Steady-state photoconductivity was studied between 80 and 300 K and showed that for as-grown samples, the lifetime went through a sharp maximum of 4.5{times}10{sup {minus}7}&hthinsp;s at 220 K, decreasing to 2.5{times}10{sup {minus}8}&hthinsp;s at 300 K. For hydrogen passivated samples, the low temperature behavior was similar but the lifetime remained high at 4.5{times}10{sup {minus}7}&hthinsp;s at 300 K, due to passivation of deep acceptors O{sub Te}. Time-resolved photoconductivity measurements gave a value of 4.6{times}10{sup {minus}8}&hthinsp;s for as-grown ZnTe in reasonably good agreement and 3.2{times}10{sup {minus}7}&hthinsp;s for Zn annealed and 3.1{times}10{sup {minus}7}&hthinsp;s for SI-ZnTe. The radiative recombination constant {ital B} was thus found to be 1.4{times}10{sup {minus}9} and 4{times}10{sup {minus}10}&hthinsp;cm{sup 3}&hthinsp;s{sup {minus}1}, respectively, at 300 K for as-grown and Zn-annealed samples. PC spectral response studies showed a maximum at 2.41 eV at 300 K corresponding to the main valence{endash}conduction band transition as well as a feature near 3.2 eV corresponding to the splitoff band. Slight shift in peak energy to 2.43 eV occurred on H surface passivation due to reduction of surface recombination velocity. {copyright} {ital 1999 American Institute of Physics.}
- OSTI ID:
- 698832
- Journal Information:
- Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 11 Vol. 86; ISSN JAPIAU; ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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