All these models are fine, but one has to be careful of the objectives.

Dear Mohammed,

The adoption, I think, it depends on your research program, e.g., the problem, objectives, scope & limitations, etc. Referring your question description around "trust" and "organization," it is related to UTAUT and TOE. In addition, whatever model you will adopt, even you can adopt the three models above mentioned, combine, adapt, or modify the models, but the essential point is the rationale of the use in the modelling. In short, you must clear about the theoretical framework behind the new model submission. Besides you may focus on what is the content of the model, you must also consider the modeling process.

God willing, it will help

What is appropriate adoption model must use in my study?

Premature for me to recommend which model but following are some suggestions on the thought process how to choose one:

I guess Mohammad, you can add flexibility and control. The trust issue is more dependent on control. The bandwidth is an important factor... switching to the CC will be influenced by external factors like bandwidth...

Any model used must appropriately tied with the decision-makers and users whom are the cloud adopters in the organisation. Understanding the influence of both groups of  adopters and understanding the various theories related to adoption, together with the objectives of your framework; will enable you to identify, modify, enhances or produced hybrid model from the theories.

There are many models to measure adoption, but if you need to rank a set of factors in adopting a particular technology you can use Garrett Ranking.

It is applied to rank a set of factors in adopting a particular technology as perceived by the sample respondents based on certain criteria.

The order of the merit assigned by the respondents is converted into scores by using the formula given by Garrett and wood worth (1977)

100 (Rij – 0.5)

Per cent position = ____________

Nj

Where,

Rij = Rank given for ith factor by jth individual

Nj = Number of factors ranked by ith individual

I strongly suggest you to read http://oss.sagepub.com/content/17/1/107.short 

Title perspective on organization innovation

it gives a good map on various adoption of innovation theories

You can consider TPB model as well. Please check whether trust model is appropriate or not?

I recommend UTAUT model, since it was formulated based on existing models like TAM. It is highly recommended that you add or modify some constructs to suit your taste.

you may use UTAUT but with some addition of independent variable which has not been used  before in this study....like culture certain impediments which can significantly affect technology adoption. 

Another direction to your question is the organizational vs. individuals perspectives... I guess you need to define your unit of analysis to see how can you manage your research method... Once you defined that, then the factors can be related to such direction. Individual research is also valid, where we use many CC applications on our own or within organizations. 

i think u can use one of the model or you combine three of model for your research but u must get justification about it by another research before

You can use ADOPT model, this is a brief about it:

ADOPT: Adoption and Diffusion Outcome Prediction Tool

ADOPT- THEORY

1- Relative Advantage for the Population

Profit orientation

Environmental orientation

Risk orientation

Enterprise scale

Management horizon

Short term constraints

2- Learnability Characteristics of the Innovation

Trialable

Innovation complexity

Observability

3- Learnability of Population

Advisory support

Group involvement

Relevant existing skills & knowledge

Innovation awareness

4- Relative Advantage of the Innovation

Relative upfront cost of innovation

Reversibility of innovation

Profit benefit in years that it is used

Future profit benefit

Time until any future profit benefits are likely to be realised

Environmental costs & benefits

Time to environmental benefit

Risk exposure

Ease and convenience

Since you are working on trust, I think you shouldn't focus on adoption models.

The use of adoption model is either disapprove or affirm it. You may as well craft your own to examine a phenomenon.

Good question and informative answers thank you all!

interesting

interesting...

logistic model

Carol Slappendel actually published a paper to clasify diffusion of innovation research into 3 perspective

look it up Article Perspectives on Innovation in Organizations

DC&MC and TAM and TOE

Choosing the appropriate adoption model for your study depends on the specific research objectives and context of your study. Let's briefly discuss the three models you mentioned – TAM (Technology Acceptance Model), TOE (Technology-Organization-Environment), and UTAUT (Unified Theory of Acceptance and Use of Technology) – and how they might align with your study on factors influencing adopters' trust in cloud computing services within organizations.

Ultimately, the choice of adoption model should align with your research questions and objectives. Given that your study involves both decision-makers and IT staff and aims to explore trust in cloud computing services within organizations, UTAUT might be the most appropriate choice. It provides a comprehensive view of adoption by considering a wide range of factors and their interactions.

However, it's crucial to review the literature and identify if any existing research has used these models in a similar context. This can provide additional insights into the most suitable model based on the existing body of knowledge. Also, consider the feasibility of data collection and the resources available for your study when making your decision

Carryout a thorough literature review to: establish research gaps, establish whether existing theoretical framework are useful for the methodology chosen if not then craft a conceptual framework you to help answer research question to address the objectives in the study?