In0.53Ga0.47As p-i-n photodiodes with transparent cadmium tin oxide contacts

Paul R. Berger, Niloy K. Dutta, George Zydzik, H. M. O'Bryan, Ursula Keller, Peter R. Smith, John Lopata, D. Sivco, A. Y. Cho

Research output: Contribution to journalArticleScientificpeer-review

8 Citations (Scopus)


A new type of p-i-n In0.53Ga0.47As photodiode having an optically transparent composite top electrode consisting of a thin semitransparent metal layer and a transparent cadmium tin oxide (CTO) layer was investigated. The composite functions as the n or p contact, an optical window, and an antireflection coating. The transparent contact also prevents shadowing of the active layer by the top electrode, thus allowing greater collection of incident light. Since the CTO contact is nonalloyed, interdiffusion into the i-region is not relevant avoiding an increased dark current. The photodiodes exhibited leakage currents of ≤8 nA and some as low as 23 pA, with reverse breakdown voltages of ≥15-17 V. Responsivity was measured using a 1.55 μm InGaAsP diode laser focused onto an unpassivated 60 μm diam p-i-n photodiode and was ≥0.41 A/W. Photoresponse of the diodes to 3 ps pulses from a Nd:YLF laser (λ=1.047 μm) was 169 and 86 ps for the 60 and 9 μm diodes, respectively. The maximum frequency response of the 9 μm diode is packaging limited, and is expected to have an intrinsic response time of 20-30 ps.

Original languageEnglish
Pages (from-to)1673-1675
Number of pages3
JournalApplied Physics Letters
Issue number14
Publication statusPublished - 1992
Externally publishedYes
Publication typeA1 Journal article-refereed

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)


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