Date of Graduation
12-2016
Document Type
Dissertation
Degree Name
Doctor of Philosophy in Microelectronics-Photonics (PhD)
Degree Level
Graduate
Department
Microelectronics-Photonics
Advisor/Mentor
Shui-Qing (fisher) Yu
Committee Member
Gregory Salamo
Second Committee Member
Hameed A. Naseem
Third Committee Member
Simon Ang
Fourth Committee Member
Zhong Chen
Keywords
Applied sciences, Gesn emitters, Infrared, Optoelectronics, Si photonics
Abstract
Conventional integrated electronics have reached a physical limit, and their efficiency has been influenced by the generated heat in the high-density electronic packages. Integrated photonic circuits based on the highly developed Si complementary-metal-oxide-semiconductor (CMOS) infrastructure was proposed as a viable solution; however, Si-based emitters are the most challenging component for the monolithic integrated photonic circuits. The indirect bandgap of silicon and germanium is a bottleneck for the further development of photonic and optoelectronic integrated circuits.
The Ge1-xSnx alloy, a group IV material system compatible with Si CMOS technology, was suggested as a desirable material that theoretically exhibits a direct bandgap when Sn composition increases. Last decade, efforts were made to develop high quality Ge1-xSnx films on Si substrate using commercial reactors. Moreover, the effect of Sn composition on the bandgap energy of Ge1-xSnx alloys was theoretically investigated.
In this work, the development of Si-based Ge1-xSnx emitters was pursued with study the temperature-dependent bandgap emission of Ge1-xSnx structures for the short-wave infrared (SWIR) wavelength range (between 1.5 to 3 µm). The photoluminescence (PL) emissions from the bandgap of Ge1-xSnx films were investigated and a direct bandgap Ge1-xSnx was demonstrated for the first time based on the careful analysis of the PL spectra line-width and also the strain-dependent bandgap concept. In addition, the Ge1-xSnx advanced structure including SiGeSn/GeSn/SiGeSn single quantum well (QW) and Ge/Ge0.92Sn0.08/Ge double heterostructures (DHS) were studied. The GeSn QW PL emission was scrutinized from 10 to 300 K and the carrier confinement was analyzed through band offset calculations in the QW structure. Moreover, the electrical and optical characteristics of n-i-p Ge/Ge0.92Sn0.08/Ge light emitting diodes (LEDs) with surface emitting and edge emitting configurations were examined at different temperatures. Additionally, the lasing performance from the DHS Ge/Ge0.89Sn0.11/Ge waveguide was experimentally investigated based on the concept of direct bandgap Ge1-xSnx films and the confinement of carriers and optical field within the Ge/Ge0.89Sn0.11/Ge structure. Finally, an optimized QW design has been proposed that features a direct bandgap Ge0.9Sn0.1 QW with Type-I band alignment favorable for the high carrier confinement and low threshold Ge1-xSnx QW devices.
Citation
Ghetmiri, S. (2016). Si-based Germanium-Tin (GeSn) Emitters for Short-Wave Infrared Optoelectronics. Graduate Theses and Dissertations Retrieved from https://scholarworks.uark.edu/etd/1824
Included in
Electronic Devices and Semiconductor Manufacturing Commons, VLSI and Circuits, Embedded and Hardware Systems Commons