Room-temperature Domain-epitaxy of Copper Iodide Thin Films for Transparent CuI/ZnO Heterojunctions with High Rectification Ratios Larger than 109

Abstract

CuI is a p-type transparent conductive semiconductor with unique optoelectronic properties, including wide band gap (3.1 eV), high hole mobility (>40 cm2 V−1 s−1 in bulk), and large room-temperature exciton binding energy (62 meV). The difficulty in epitaxy of CuI is the main obstacle for its application in advanced solid-state electronic devices. Herein, room-temperature heteroepitaxial growth of CuI on various substrates with well-defined in-plane epitaxial relations is realized by reactive sputtering technique. In such heteroepitaxial growth the formation of rotation domains is observed and hereby systematically investigated in accordance with existing theoretical study of domain-epitaxy. The controllable epitaxy of CuI thin films allows for the combination of p-type CuI with suitable n-type semiconductors with the purpose to fabricate epitaxial thin film heterojunctions. Such heterostructures have superior properties to structures without or with weakly ordered in-plane orientation. The obtained epitaxial thin film heterojunction of p-CuI(111)/n-ZnO(00.1) exhibits a high rectification up to 2 × 109 (±2 V), a 100-fold improvement compared to diodes with disordered interfaces. Also a low saturation current density down to 5 × 10−9 Acm−2 is formed. These results prove the great potential of epitaxial CuI as a promising p-type optoelectronic material.

Room-temperature synthesized copper iodide thin film as degenerate p-type transparent conductor with a boosted figure of merit

“…The obtained CuI thin films are textured with (111)-orientation in the pure γ-phase, which is consistent with our previous report (35). The crystal structure characterization is shown in Fig.…”

“…Our results underscore the great potential of CuI applied as p-type transparent electrodes. CuI is also compatible with many other n-type TCs for active device structures, such as transparent CuI/ZnO bipolar diodes (35,36). Besides diodes, CuI/n-type TC tunneling contacts also appear attractive and could be a further direction of research.…”

“…with most crystalline electronic materials (35). The realization of highly rectifying bipolar diodes of CuI/ZnO (current on/off-ratio above 1 × 10 9 at ±2 V) opens up the application of CuI in transparent electronics (35,36). Such advantageous properties make CuI a promising p-type transparent electronic material.…”

“…These results indicate significant advances in the development of p-type TCs toward their practical use. with most crystalline electronic materials (35). The realization of highly rectifying bipolar diodes of CuI/ZnO (current on/off-ratio above 1 × 10 9 at ±2 V) opens up the application of CuI in transparent electronics (35,36).…”

Гетероструктура Для Обращенного Диода На Основе Электроосажденного В Импульсном Режиме Наномассива Оксида Цинка И Изготовленной Методом SILAR Пленки Иодида Меди

“…Во всех этих рабо-тах гетероструктуру p-CuI/n-ZnO рассматривают как основу прозрачных и полупрозрачных ультрафиолето-вых датчиков диодного типа [14,15] или биполярных пленочных диодов [16][17][18][19]. Нам не удалось отыскать в литературе данных о создании обращенного диода с такой гетероструктурой.…”