Large Negative Thermal Quenching and Broadening Lineshape Analysis of Acceptor-Associated Yellow Luminescence in Si-Doped GaN

Abstract

The yellow luminescence (YL) is a famous acceptorassociated light emission phenomenon in GaN, which is a technologically important wide-bandgap semiconductor having tremendous applications in short-wavelength optoelectronic devices and high-power/high-temperature electronic devices. However, there have been few studies on the broadening lineshape analysis and substantial negative thermal quenching of the YL band in GaN. In this article, the large negative thermal quenching (NTQ) phenomenon of the YL band in a series of Si-doped GaN samples is observed and investigated in detail under the sub-bandgap optical excitation, which is unobservable under the usual above-bandgap optical excitation. Based on rate equations of holes, a simple model is developed to quantitatively analyze the observed NTQ data, unveiling that the thermal transfer of holes excited from the shallow acceptors located at ∼300 meV above the valence band maximum to the YL deep acceptors shall be responsible for the observed large NTQ in the Si-doped GaN. Above and beyond, the underdamped multimode Brownian oscillator (MBO) theory was employed to analyze the YL lineshape at 290 K. Several important physical parameters governing the YL process, such as the Huang−Rhys factor, zero-phonon line location, dissipating coefficient of acoustic phonon bath, etc., were thus determined. The YL deep acceptor level was estimated to be located at ∼840 meV above the valence band maximum.

Manipulation of Temperature-Dependent Luminescence Behaviors of Mn4+-Activated Fluoride Phosphors

“…Therefore, suppressing or even reversing the thermal decline of solid luminescence, although a serious challenge, is highly desirable. Several different models have been proposed to interpret the TQ behavior of solid luminescence. − But only in recent years has a large negative thermal quenching (NTQ) phenomenon been firmly demonstrated in the narrow-band red luminescence of Mn 4+ ions in fluoride phosphors of K 2 SiF 6 , K 2 TiF 6 , Rb 2 SiF 6 , etc., − as well as in the broad-band yellow luminescence of deep acceptors in the wide bandgap semiconductor of GaN. , The discovery and demonstration of large NTQ in solid luminescence is of clearly both scientific and technological significance as well as broad interest. For instance, its photophysical mechanism is very interesting and could be very helpful for technologically solving the severe thermal degradation problem in phosphor-converted white LEDs which are the major devices in the state-of-the-art solid-state lighting revolution.…”