Ga1-xAlxSb avalanche photodiodes: Resonant impact ionization with very high ratio of ionization coefficients

Author

Hildebrand, O. ; Kuebart, W. ; Benz, K.W. ; Pilkuhn, M.H.

Author_Institution

Physikalisches Institut, Universität Stuttgart, Stuttgart, Germany

Volume

17

Issue

2

fYear

1981

fDate

2/1/1981 12:00:00 AM

Firstpage

284

Lastpage

288

Abstract

The liquid-phase epitaxy and device fabrication of p-n and p-i-n Ga1-xAlxSb avalanche photodiodes is described. Breakdown voltages up to 95 V and dark currents of 10^-4A/cm²have been obtained. With p-i-n diodes we have measured the impact ionization coefficients α (electrons) and β (holes) with different composition and temperature. A resonant enhancement of the hole ionization coefficient is found for $x = 0.065$ (300 K) where the ratio $\\beta /\\alpha$ exceeds values of 20. This effect is attributed to impact ionization initiated by holes from the split-off valence band: if the spin orbit splitting Δ is equal to the bandgap energy Eg, the threshold energy for hole initiated impact ionization reaches the smallest possible value ( $E_{i} = E_{g}$ ) and the ionization process occurs with zero momentum. This leads to a strong increase of β at $\\Delta /E_{g} = 1$ . The experimentally determined dependence of ionization coefficients on threshold energy is compared with theoretical expectations.

Keywords

Avalanche photodiodes; Charge carrier processes; Optical fiber receivers; Piezoelectric transducers; Avalanche photodiodes; Charge carrier processes; Dark current; Epitaxial growth; Extraterrestrial measurements; Fabrication; Impact ionization; P-i-n diodes; PIN photodiodes; Temperature;

fLanguage

English

Journal_Title

Quantum Electronics, IEEE Journal of

Publisher

ieee

ISSN

0018-9197

Type

jour

DOI

10.1109/JQE.1981.1071068

Filename

1071068