Review of deep ultraviolet photodetector based on gallium oxide

Abstract

Ultraviolet (UV) photodetectors (PDs) have drawn great attention in recent years due to their potential application in civil and military fields. Because of its ultrawide bandgap, low cost, strong radiation hardness, and high thermal and chemical stability with high visible-light transparency, Ga 2 O 3 is regarded as the most promising candidate for UV detection. Furthermore, the bandgap of Ga 2 O 3 is as high as 4.7-4.9 eV, directly corresponding to the solar-blind UV detection band with wavelength less than 280 nm. There is no need of doping in Ga 2 O 3 to tune its bandgap, compared to AlGaN, MgZnO, etc, thereby avoiding alloy composition fluctuations and phase separation. At present, solar-blind Ga 2 O 3 photodetectors based on single crystal or amorphous Ga 2 O 3 are mainly focused on metal-semiconductor-metal and Schottky photodiodes. In this work, the recent achievements of Ga 2 O 3 photodetectors are systematically reviewed. The characteristics and performances of different photodetector structures based on single crystal Ga 2 O 3 and amorphous Ga 2 O 3 thin film are analyzed and compared. Finally, the prospects of Ga 2 O 3 UV photodetectors are forecast.

Recent Progress of Deep Ultraviolet Photodetectors using Amorphous Gallium Oxide Thin Films

“…[ 4 ] Many kinds of crystalline gallium oxide UV PDs including bulk, thin films, and nanostructures have been demonstrated and summarized in several review articles recently. [ 5–8 ]…”

“…[4] Many kinds of crystalline gallium oxide UV PDs including bulk, thin films, and nanostructures have been demonstrated and summarized in several review articles recently. [5][6][7][8] According to common understanding of semiconductors, properties of crystalline materials with limited defects are usually superior compared with their amorphous counterparts. For example, the performance of solar cells or transistors using crystalline Si is better than amorphous ones because the carrier mobility of crystalline Si is about 200 cm 2 V À1 s À1 , which is much higher than the value of amorphous Si (%1 cm 2 V À1 s À1 ).…”

Improvement of the Deep UV Sensor Performance of a β-Ga2O3 Photodiode by Coupling of Two Planar Diodes

“…VER the past 5 years, significant efforts has been conducted on new forms of ultraviolet (UV) photodiodes for a wide range of applications such as in the military, environmental, medical and industrial markets which require the sensor to operate in harsh situations [1]. The most common commercial UV photodiodes are Si-based, but these possess limited sensitivity at UV wavelengths [2]. Wide bandgap semiconductor materials, such as MgZnO and AlGaN, had been reported as an alternative to Si, but it remains a challenge to achieve good crystalline quality as a result of the heavy doping levels needed [3].…”

Солнечно-слепые детекторы УФ-излучения на основе пленок beta-Ga-=SUB=-2-=/SUB=-O-=SUB=-3-=/SUB=-

“…В ряде работ приведены зависимости спектрального отклика на излучение от длины волны для структур на основе оксида галлия, полученных различными способами [12][13][14]. К настоящему времени опубликован ряд обзорных статей, описывающих способы получения объемных кристаллов и пленок β-Ga 2 O 3 , их свойства и характеристики различных устройств, изготовленных на этом материале [15][16][17][18][19]. Обобщая результаты большого количества исследований, можно сказать, что максимальная чувствительность таких детекторов наблюдается в диапазоне длин волн 230−250 нм, резкий спад чувствительности -при длинах волн > 250 нм.…”