Characterization of InGaN Quantum Wells Grown by Molecular Beam Epitaxy (MBE) Using Ammonia as the Nitrogen Source
- PDF / 43,431 Bytes
- 5 Pages / 612 x 792 pts (letter) Page_size
- 23 Downloads / 205 Views
Electrical Engineering Department, Columbia University, New York, NY 10027
ABSTRACT Single quantum well InGaN was grown by molecular beam epitaxy with ammonia as the nitrogen source. The samples were grown on (0001) sapphire substrates. The photoluminescence (PL) intensity of InGaN quantum wells showed band-edge emissions at 2.71eV at low temperature (10 K). PL was investigated as a function of excitation intensity and temperature. The relationship between PL intensity and excitation intensity, as well as the relationship between PL intensity and lattice temperature was studied. Also studied was the combined effect of temperature and intensity variation. Detailed results are reported here. INTRODUCTION III-V GaN based semiconductors have recently attracted attention for their potential applications as multicolor light emitters, solar-blind ultraviolet detectors, and high power/high-temperature electronics. In xGa1-x N alloy systems and related heterostructures such as quantum wells (QWs) are especially attracting attention because they are used as active layers for high-brightness blue, green, and yellow light emitting diodes (LEDs) [1,2] and cw blue laser diodes (LDs) [3]. A large number of studies have been reported on the optical properties of InGaN epilayers and InGaN/GaN QW structures particularly pressure dependent PL studies [4] on InGaN/GaN multiple quantum wells , time resolved PL studies of InGaN/GaN single quantum wells at room temperature [5], determination of PL mechanism in InGaN quantum wells [6] and temperature dependent PL line shapes in InGaN [7]. Despite the commercial success of InGaN based LEDs, their optical emission properties are not completely understood. EXPERIMENT The InGaN SQW structures with varying thickness examined in this study were grown by molecular beam epitaxy (MBE) with ammonia used as the nitrogen source. The samples were grown on (0001) sapphire substrates. Before the growth, the sapphire substrate was cleaned by an SVT Associates RF nitrogen source at 800°C for 10 minutes. We used low substrate temperature (60 K ( not shown here) the carriers are becoming thermalized while below T
Data Loading...
