Low-temperature carrier transport across InGaN multiple quantum wells: Evidence of ballistic hole transport

Abstract

Carrier transport across polar n-type InGaN/GaN multiple quantum wells (MQWs) has been studied by time-resolved photoluminescence (PL) using an optical marker technique. Efficiency of the hole transfer into the marker well experienced a nonmonotonous temperature dependence. First, as the temperature was lowered below room temperature, the number of transferred holes decreased because of the decreased efficiency of the thermionic emission. However, when the temperature was lowered below ∼80 K, the number of transferred holes experienced a significant rise. In addition, the low-temperature hole transport across the MQW structure was very fast, <3 ps. These features indicate that the low-temperature hole transport across the MQWs is ballistic or quasiballistic. Comparison of PL data for structures with different MQW parameters suggests that at low temperatures the hole mean-free path is about 10 nm. Probably, hole transport via light hole and split-off valence bands contributes to this high value.

Impact of random alloy fluctuations on inter-well transport in InGaN/GaN multi-quantum well systems: an atomistic non-equilibrium Green’s function study

“…However, for wider barrier width this effect is strongly reduced. Overall, our theoretical findings of significant ballistic hole transport for narrower barrier width, which decreases with increasing barrier width, is consistent with recent experimental studies [16].…”

“…Overall, these initial studies indicate that using InGaN barriers with low In content are beneficial for increasing the ballistic transport in InGaN MQW systems, and thus potentially enabling an improved distribution of carriers between the different QWs in an MQW structure. This finding may explain the experimental observation made in the work by Marcinkevičius et al [16]. To shed further light on the influence of InGaN barriers on the transport properties of InGaN MQWs, future studies may target a variety of different questions.…”

“…On the other hand, experimental studies observe significant ballistic hole transport through InGaN MQWs [16]. Understanding hole transport properties in these structures is important since ideally the carrier density (electrons and holes) should be evenly distributed in the wells forming the MQW; this ensures that all wells contribute to the light emission process.…”

Plasmonic Light Scattering via Au Nanoparticles for Extended Photo Absorption in InGaN/GaN Multiquantum Wells for Unbiased Stable Solar-Driven Water Splitting

“…This structure enables strain relaxation during InGaN/GaN MQW formation. Furthermore, MQWs might confine the hole carriers to the depletion layer, − from whence they could be carried to the interfaces between the semiconductor and the electrolyte. As a result, by increasing the number of hole carriers at the interface, this structure improves the photoresponse .…”

Influence of low temperature on the electrophysical and noise characteristics of UV LEDs based on InGaN/GaN quantum well structures

“…A drop of luminescence intensity and external quantum efficiency with temperature rise was described in several papers in the ranges: from 280 to 340 [1], from 300 to 500 [2], from 290 to 360 K [3]. In this respect, research of radiating [4,5] and noise characteristics [6] of lightemitting diodes at low temperatures is promising since they can be used at negative ambient temperatures (in freezing chambers). Temperature decrease increases the luminous flux, reduces the LED degradation rate, reduces the semiconductor diode noise density.…”