Photodetection Properties of Nonpolar a‐Plane GaN Grown by Three Approaches Using Plasma‐Assisted Molecular Beam Epitaxy

Abstract

Present work focuses on improving the quality of nonpolar a‐plane GaN thin films by introducing unconventional new efficient growth conditions without compromising their UV photodetection properties. These epitaxial thin films are grown on r‐plane sapphire using three different growth approaches by plasma‐assisted molecular beam epitaxy (PAMBE). In situ reflection high‐energy electron diffraction (RHEED) analysis is performed during and after the growth to monitor the growth mode, and it is found that the films assumed desired 2D mode during the growth. The crystalline quality and the phase purity of the films are assessed with the help of high‐resolution X‐ray diffraction and Raman spectroscopy. All the films are found to contain compressive stress, which indicate that all the films are strained and epitaxial. The temporal response is carried out in all the three batches, which is very stable. Sensitivity, responsivity, transit time, and gain values are estimated. Highest responsivity and the corresponding gain are found to be around 25 AW−1, 86.47 at 1 V bias, respectively. These are the highest reported values so far for a‐plane GaN at such low voltages.

Group III-Nitrides and Their Hybrid Structures for Next-Generation Photodetectors

“…These results underlined the importance of aligning the contact electrodes along the favorable azimuth direction in order to restrict the transport of the charge carriers. In a subsequent work, Pant et al [51] have further shown [48].…”

Non-Polar Gallium Nitride for Photodetection Applications: A Systematic Review

“…In recent years, several attempts were accomplished to enhance the efficiency of UV photodetectors by using wide and direct bandgap semiconductor materials such as aluminum gallium nitride (AlGaN)/aluminum indium gallium nitride (AlInGaN), aluminum nitride (AlN), gallium nitride (GaN) and zinc oxide (ZnO), and other organic compounds [12,[14][15][16][17][18]; the range of the bandgaps of these materials is 0.7-6.4 eV. Thus, these materials are deemed suitable for the use of wide bandgap photodetectors [17,19,20]. However, the exciton-binding energy of these materials is 40-52 meV, resulting in a hindrance of the devices' performance [16,21,22].…”

“…Therefore, a non-polar GaN-based photodetector would exhibit a faster response with higher efficiency. Several groups have reported the use of the non-polar growth direction to produce GaN-based photodetectors along the non-polar direction as an alternative for c-orientated photodetectors [19,23,[30][31][32]. However, it is noteworthy that non-polar GaN grown on sapphire or silicon (Si) substrates portrayed low crystal quality (far from device requirement) with a broad full width at half maximum (FWHM) of ∼0.5-0.6 • as compared to the c-orientated GaN growth (less than 0.1 • ) [2,7,19,23,30,[33][34][35].…”

“…Several groups have reported the use of the non-polar growth direction to produce GaN-based photodetectors along the non-polar direction as an alternative for c-orientated photodetectors [19,23,[30][31][32]. However, it is noteworthy that non-polar GaN grown on sapphire or silicon (Si) substrates portrayed low crystal quality (far from device requirement) with a broad full width at half maximum (FWHM) of ∼0.5-0.6 • as compared to the c-orientated GaN growth (less than 0.1 • ) [2,7,19,23,30,[33][34][35]. This is mainly attributed to the anisotropic crystallographic mismatch owing to dissimilar lattice structures and mismatches in the coefficients of thermal expansion between non-polar GaN epitaxial layers and the substrates [19,23,31,36,37].…”

Анизотропные напряжения в слоях GaN(1120) на подложке r-Al-=SUB=-2-=/SUB=-O-=SUB=-3-=/SUB=- при хлорид-гидридной газофазной эпитаксии

“…Однако этот метод не подходит для коммерческих целей из-за его низкой производительности и ограничений по размерам. Наиболее популярными способами изготовления неполярных квазиподложек является гетероэпитаксиальное выращивание неполярного GaN на чужеродных подложках с использованием осаждения из металлоорганических соединений (MOCVD) [5], метод молекулярнолучевой эпитаксии (MBE) [6] и метод хлорид-гидридной газофазной эпитаксии (HVPE) [7].…”